U.S. patent application number 11/269525 was filed with the patent office on 2006-08-03 for selection of host cells expressing protein at high levels.
This patent application is currently assigned to Chromagenics B.V.. Invention is credited to Theodorus H. J. Kwaks, Arie P. Otte, Richard G. A. B. Sewalt, Henricus J. M. van Blokland.
Application Number | 20060172382 11/269525 |
Document ID | / |
Family ID | 34929819 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060172382 |
Kind Code |
A1 |
Otte; Arie P. ; et
al. |
August 3, 2006 |
Selection of host cells expressing protein at high levels
Abstract
The invention provides a DNA molecule comprising a
multicistronic transcription unit coding for i) a selectable marker
polypeptide functional in a eukaryotic host cell, and for ii) a
polypeptide of interest, the polypeptide of interest having a
translation initiation sequence separate from that of the
selectable marker polypeptide, characterized in that the coding
sequence for the polypeptide of interest is downstream from the
coding sequence for the selectable marker in said multicistronic
transcription unit, and the nucleic acid sequence coding for the
selectable marker polypeptide comprises a mutation that decreases
the translation efficiency of the selectable marker in a eukaryotic
host cell. The invention also provides methods for obtaining host
cells expressing a polypeptide of interest, said host cells
comprising the DNA molecules of the invention. The invention
further provides the production of polypeptides of interest,
comprising culturing host cells comprising the DNA molecules
according to the invention.
Inventors: |
Otte; Arie P.; (Amersfoort,
NL) ; van Blokland; Henricus J. M.; (Wijdewormer,
NL) ; Kwaks; Theodorus H. J.; (Amsterdam, NL)
; Sewalt; Richard G. A. B.; (Arnhem, NL) |
Correspondence
Address: |
TRASK BRITT
P.O. BOX 2550
SALT LAKE CITY
UT
84110
US
|
Assignee: |
Chromagenics B.V.
Leiden
NL
|
Family ID: |
34929819 |
Appl. No.: |
11/269525 |
Filed: |
November 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60626301 |
Nov 8, 2004 |
|
|
|
60696610 |
Jul 5, 2005 |
|
|
|
Current U.S.
Class: |
435/69.1 ;
435/320.1; 435/326; 530/388.1; 536/23.53 |
Current CPC
Class: |
C07K 16/00 20130101;
C07K 16/30 20130101; C07K 14/00 20130101 |
Class at
Publication: |
435/069.1 ;
435/320.1; 435/326; 530/388.1; 536/023.53 |
International
Class: |
C07H 21/04 20060101
C07H021/04; C12P 21/06 20060101 C12P021/06; C12N 5/06 20060101
C12N005/06; C07K 16/18 20060101 C07K016/18 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2004 |
EP |
04105593.0 |
Claims
1. A DNA molecule comprising a multicistronic transcription unit
coding for i) a selectable marker polypeptide functional in a
eukaryotic host cell, and for ii) a polypeptide of interest,
wherein the polypeptide of interest has a translation initiation
sequence separate from that of the selectable marker polypeptide,
and wherein the coding sequence for the polypeptide of interest is
downstream from the coding sequence for the selectable marker in
said multicistronic transcription unit, and wherein the nucleic
acid sequence coding for the selectable marker polypeptide in the
coding strand comprises a translation start sequence chosen from
the group consisting of: a) an ATG startcodon in a non-optimal
context for translation initiation, comprising the sequence
(C/T)(A/T/G)(A/T/G)ATG(A/T/C) wherein the startcodon is underlined;
b) a GTG startcodon; c) a TTG startcodon; d) a CTG startcodon; e) a
ATT startcodon; and f) a ACG startcodon.
2. A DNA molecule according to claim 1, wherein the translation
start sequence in the coding strand for the selectable marker
polypeptide comprises a GTG startcodon.
3. A DNA molecule according to claim 1, wherein the translation
start sequence in the coding strand for the selectable marker
polypeptide comprises a TTG startcodon.
4. A DNA molecule according to claim 1, wherein the sequence
encoding the selectable marker polypeptide has no ATG sequence in
the coding strand following the startcodon of the selectable marker
polypeptide up to the startcodon of the polypeptide of
interest.
5. A DNA molecule according to claim 4, wherein any sequence ATG
when present in frame and coding for methionine in the sequence
coding for the wild type marker polypeptide is mutated to code for
an amino acid chosen from the group consisting of valine,
threonine, isoleucine, and leucine.
6. A DNA molecule according to claim 1, wherein the selectable
marker protein provides resistance against lethal or
growth-inhibitory effects of a selection agent.
7. A DNA molecule according to claim 6, wherein said selection
agent is an antibiotic.
8. A DNA molecule according to claim 6, wherein said selection
agent is chosen from the group consisting of: zeocin, puromycin,
blasticidin, hygromycin, neomycin, methotrexate, methionine
sulphoximine and kanamycin.
9. A DNA molecule according to claim 6, wherein the selection agent
is zeocin.
10. A DNA molecule according to claim 6, wherein the selection
agent is blasticidin.
11. A DNA molecule according to claim 6, wherein the selection
agent is puromycin.
12. A DNA molecule according to claim 6, wherein the selectable
marker protein is encoded by the neomycin resistance gene.
13. A DNA molecule according to claim 6, wherein the selectable
marker protein is encoded by the dhfr gene.
14. A DNA molecule according to claim 1, wherein the selectable
marker polypeptide further comprises a mutation that reduces the
activity of the selectable marker polypeptide compared to its
wild-type counterpart.
15. A DNA molecule according to claim 14, wherein the selectable
marker polypeptide is a zeocin resistance polypeptide wherein
proline at position 9 has been changed into a different amino
acid.
16. A DNA molecule according to claim 1, wherein the coding
sequence of the polypeptide of interest comprises an optimal
translation start sequence, comprising the sequence (A/G)CCATGG
wherein the startcodon is underlined.
17. An expression cassette comprising a DNA molecule according to
claim 1, said expression cassette further comprising a promoter
upstream of said multicistronic expression unit and being
functional in a eukaryotic host cell for initiating transcription
of the multicistronic expression unit, and said expression cassette
further comprising a transcription termination sequence downstream
of the multicistronic expression unit.
18. An expression cassette according to claim 17, further
comprising at least one chromatin control element, chosen from the
group consisting of a matrix or scaffold attachment region
(MAR/SAR), an insulator sequence, a universal chromatin opening
element (UCOE), and an anti-repressor (STAR) sequence.
19. An expression cassette according to claim 18, wherein said at
least one chromatin control element is the chicken lysosyme 5'
MAR.
20. An expression cassette according to claim 18, wherein said
chromatin control element is an anti-repressor sequence.
21. An expression cassette according to claim 20, wherein said
anti-repressor sequence is chosen from the group consisting of: a)
any one of SEQ. ID. NO.1 through SEQ. ID. NO.66; b) fragments of
any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 66, wherein said
fragments have anti-repressor activity; c) sequences that are at
least 70% identical in nucleotide sequence to a) or b) wherein said
sequences have anti-repressor activity; and d) the complement to
any one of a) to c).
22. An expression cassette according to claim 21, wherein said
expression cassette comprises one of: a) SEQ. ID. NO.66, b) a
fragment of a) having anti-repressor activity; c) a sequence that
is at least 70% identical in nucleotide sequence to a) or b)
wherein said sequence has anti-repressor activity, wherein a), b)
or c) is positioned upstream of the promoter that drives
transcription of the multicistronic gene.
23. An expression cassette according to claim 17, wherein said
multicistronic gene is flanked on both sides by at least one
anti-repressor sequence.
24. An expression cassette according to claim 23, wherein said
anti-repressor sequence is chosen from the group consisting of: a)
any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 65; b) fragments of
any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 65, wherein said
fragments have anti-repressor activity; c) sequences that are at
least 70% identical in nucleotide sequence to a) or b) wherein said
sequences have anti-repressor activity; and d) the complement to
any one of a) to c).
25. An expression cassette according to claim 23, comprising: 5'-
anti-repressor sequence A--anti-repressor sequence
B-promoter--multicistronic gene encoding the functional selectable
marker protein and downstream thereof the polypeptide of
interest--transcription termination sequence--anti-repressor
sequence C-3', wherein anti-repressor sequences A and C may be the
same or different and are chosen from the group consisting of: a)
any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 65; b) fragments of
any one of the sequences of a), said fragments having
anti-repressor activity; c) sequences that are at least 70%
identical in nucleotide sequence to a) or b) wherein said sequences
have anti-repressor activity, and wherein anti-repressor sequence B
is chosen from the group consisting of: i) SEQ. ID. NO. 66, ii) a
fragment of i) having anti-repressor activity; and iii) a sequence
that is at least 70% identical in nucleotide sequence to i) or ii)
wherein said sequence has anti-repressor activity.
26. An expression cassette according to claim 25, wherein
anti-repressor sequences A and C are chosen from: a) SEQ. ID. NO.
7; b) fragments of one of the sequences of a), said fragments
having anti-repressor activity; and c) sequences that are at least
70% identical in nucleotide sequence to a) or b) wherein said
sequences have anti-repressor activity.
27. An expression cassette according to claim 17, wherein the
polypeptide of interest is a part of a multimeric protein.
28. An expression cassette according to claim 27, wherein the
polypeptide of interest is chosen from the group consisting of an
immunoglobulin light chain and an immunoglobulin heavy chain.
29. An expression cassette according to claim 17, further
comprising: a) a transcription pause (TRAP) sequence upstream of
said promoter and being in a 5' to 3' direction; or b) a TRAP
sequence downstream of said transcription termination sequence and
being in a 3' to 5' orientation; or c) both a) and b); wherein a
TRAP sequence is a sequence which when placed into a transcription
unit, results in a reduced level of transcription in the nucleic
acid present on the 3' side of the TRAP when compared to the level
of transcription observed in the nucleic acid on the 5' side of the
TRAP.
30. An expression cassette according to claim 30, wherein said TRAP
is SEQ. ID. NO. 142.
31. A DNA molecule comprising a sequence encoding a selectable
marker polypeptide functional in a eukaryotic cell, wherein: i) the
sequence encoding the selectable marker polypeptide in the coding
strand comprises a translation start sequence chosen from the group
consisting of: a) an ATG startcodon in a non-optimal context for
translation initiation, comprising the sequence
(C/T)(A/T/G)(A/T/G)ATG(A/T/C) wherein the startcodon is underlined;
b) a GTG startcodon; c) a TTG startcodon; d) a CTG startcodon; e) a
ATT startcodon; and f) a ACG startcodon, and wherein the DNA
molecule ii) in the coding strand of the sequence defining the
selectable marker polypeptide downstream of the non-optimal
startcodon and up to the stopcodon is devoid of ATG sequences.
32. A host cell comprising a DNA molecule according to claim 1.
33. A host cell comprising a DNA molecule according to claim 2.
34. A host cell comprising a DNA molecule according to claim 3.
35. A host cell comprising a DNA molecule according to claim 4.
36. A host cell comprising an expression cassette according to
claim 17.
37. A host cell comprising an expression cassette according to
claim 18.
38. A host cell comprising a DNA molecule according to claim
31.
39. A host cell according to claim 32, which is a eukaryotic host
cell.
40. A host cell according to claim 39, which is a mammalian host
cell.
41. A host cell according to claim 40, being a Chinese Hamster
Ovary (CHO) cell.
42. A method for generating a host cell expressing a polypeptide of
interest, the method comprising the steps of: a) introducing into a
plurality of precursor cells a DNA molecule according to claim 1,
and b) culturing the generated cells under conditions selecting for
expression of the selectable marker polypeptide, and c) selecting
at least one host cell producing the polypeptide of interest.
43. A method for generating a host cell expressing a polypeptide of
interest, the method comprising the steps of: a) introducing into a
plurality of precursor cells an expression cassette according to
claim 17, and b) culturing the generated cells under conditions
selecting for expression of the selectable marker polypeptide, and
c) selecting at least one host cell producing the polypeptide of
interest.
44. A method for producing a polypeptide of interest, comprising
culturing a host cell, said host cell comprising an expression
cassette according to claim 17, and expressing the polypeptide of
interest from the expression cassette.
45. A method for producing a polypeptide of interest, comprising
culturing a host cell, said host cell comprising an expression
cassette according to claim 18, and expressing the polypeptide of
interest from the expression cassette.
46. A method according to claim 44, further comprising isolating
the polypeptide of interest.
47. A method according to claim 45, further comprising isolating
the polypeptide of interest.
48. An RNA molecule having the sequence of the transcription
product of a DNA molecule according to claim 1.
49. A selectable marker polypeptide encoded by a DNA molecule
according to claim 31, wherein the selectable marker polypeptide
provides resistance against lethal or growth-inhibitory effects of
a selection agent chosen from the group consisting of: zeocin,
puromycin, blasticidin, hygromycin, neomycin, methotrexate,
methionine sulphoximine, and kanamycin, with the proviso that the
selectable marker polypeptide is not the blasticidine resistance
protein having methionine as first amino acid (SEQ. ID. NO.
111).
50. A DNA molecule comprising a sequence encoding a polypeptide
conferring resistance to zeocin in eukaryotic cells, wherein the
sequence in the coding strand comprises a translation start
sequence chosen from the group consisting of: a) an ATG startcodon
in a non-optimal context for translation initiation, comprising the
sequence (C/T)(A/T/G)(A/T/G)ATG(A/T/C) wherein the startcodon is
underlined; b) a GTG startcodon; c) a TTG startcodon; d) a CTG
startcodon; e) a ATT startcodon; and f) a ACG startcodon.
51. A DNA molecule according to claim 50, wherein the sequence in
the coding strand comprises a GTG startcodon.
52. A DNA molecule according to claim 50, wherein the sequence in
the coding strand comprises a TTG startcodon.
53. A DNA molecule comprising a sequence encoding a polypeptide
conferring resistance to blasticidin in eukaryotic cells, wherein
the sequence in the coding strand comprises a translation start
sequence chosen from the group consisting of: a) an ATG startcodon
in a non-optimal context for translation initiation, comprising the
sequence (C/T)(A/T/G)(A/T/G)ATG(A/T/C) wherein the startcodon is
underlined; b) a GTG startcodon; c) a TTG startcodon; d) a CTG
startcodon; e) a ATT startcodon; and f) a ACG startcodon.
54. A DNA molecule according to claim 53, wherein the sequence in
the coding strand comprises a GTG startcodon.
55. A DNA molecule according to claim 53, wherein the sequence in
the coding strand comprises a TTG startcodon.
56. An expression cassette according to claim 17, wherein said
promoter is a CMV promoter.
57. An expression cassette according to claim 17, wherein said
promoter is an SV40 promoter.
58. A DNA molecule comprising two expression cassettes according to
claim 17, wherein the first expression cassette encodes an antibody
heavy chain as polypeptide of interest, and wherein the second
expression cassette encodes an antibody light chain as polypeptide
of interest, and wherein the first and second expression cassette
encode different selectable marker polypeptides.
59. A DNA molecule according to claim 58, further comprising a
functional promoter operably linked to a sequence encoding
dhfr.
60. A method for producing an antibody, the method comprising
culturing a eukaryotic cell and harvesting the antibody from the
cells in the culture or from the culture supernatant or from both
the cells and the culture supernatant, wherein the cell comprises a
first and a second multicistronic transcription unit each under
control of an independent promoter, wherein the first
multicistronic transcription unit encodes a first functional
selectable marker polypeptide and the heavy chain of the antibody,
and wherein the second multicistronic transcription unit encodes a
second functional selectable marker polypeptide and the light chain
of the antibody, and wherein the heavy and light chain of the
antibody have translation initiation sequences separate from that
of the first and second selectable marker polypeptides
respectively, and wherein the coding sequences for the heavy and
light chains of the antibody are downstream of the coding sequences
of the first and second functional selectable markers in the first
and second multicistronic transcription units respectively, and
wherein the sequences encoding the first and second selectable
marker polypeptides have no ATG sequence in the coding strands
following the startcodons of the selectable marker polypeptides up
to the startcodons of the heavy and light chain respectively, and
wherein the sequences coding for the first and second selectable
marker polypeptide in the coding strand comprise a translation
start sequence each independently chosen from the group consisting
of: a) an ATG startcodon in a non-optimal context for translation
initiation, comprising the sequence (C/T)(AIT/G)(A/T/G)ATG(A/T/C)
wherein the startcodon is underlined; b) a GTG startcodon; c) a TTG
startcodon; d) a CTG startcodon; e) a ATT startcodon; and f) a ACG
startcodon.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The invention relates to the field of molecular biology and
biotechnology. More specifically the present invention relates to
means and methods for improving the selection of host cells that
express proteins at high levels.
[0002] Proteins can be produced in various host cells for a wide
range of applications in biology and biotechnology, for instance as
biopharmaceuticals. Eukaryotic and particularly mammalian host
cells are preferred for this purpose for expression of many
proteins, for instance when such proteins have certain
posttranslational modifications such as glycosylation. Methods for
such production are well established, and generally entail the
expression in a host cell of a nucleic acid (also referred to as
`transgene`) encoding the protein of interest. In general, the
transgene together with a selectable marker gene is introduced into
a precursor cell, cells are selected for the expression of the
selectable marker gene, and one or more clones that express the
protein of interest at high levels are identified, and used for the
expression of the protein of interest.
[0003] One problem associated with the expression of transgenes is
that it is unpredictable, stemming from the high likelihood that
the transgene will become inactive due to gene silencing (McBurney
et al., 2002), and therefore many host cell clones have to be
tested for high expression of the transgene.
[0004] Methods to select recombinant host cells expressing
relatively high levels of desired proteins are known.
[0005] One method describes the use of selectable marker proteins
with mutations in their coding sequence that diminish, but not
destroy the function of the marker (e.g., WO 01/32901). The
rationale is that higher levels of the mutant marker expression are
required when selection conditions are employed and therefore
selection for high expression of the marker is achieved, therewith
concomitantly selecting host cells that also express the gene of
interest at high levels.
[0006] Another method makes use of a selection marker gene under
control of a promoter sequence that has been mutated such that the
promoter has an activity level substantially below that of its
corresponding wild type (U.S. Pat. No. 5,627,033).
[0007] Another method describes the use of an impaired dominant
selectable marker sequence, such as neomycin phosphotransferase
with an impaired consensus Kozak sequence, to decrease the number
of colonies to be screened and to increase the expression levels of
a gene of interest that is co-linked to the dominant selectable
marker (U.S. Pat. Nos. 5,648,267 and 5,733,779). In preferred
embodiments therein, the gene of interest is placed within an
(artificial) intron in the dominant selectable marker. The gene of
interest and the dominant selectable marker are in different
transcriptional cassettes and each contains its own eukaryotic
promoter in this method (U.S. Pat. Nos. 5,648,267 and
5,733,779).
[0008] Another method uses the principle of a selectable marker
gene containing an intron that does not naturally occur within the
selectable gene, wherein the intron is capable of being spliced in
a host cell to provide mRNA encoding a selectable protein and
wherein the intron in the selectable gene reduces the level of
selectable protein produced from the selectable gene in the host
cell (European Patent 0724639 B1).
[0009] In yet another method, DNA constructs are used comprising a
selectable gene positioned within an intron defined by a 5' splice
donor site comprising an efficient splice donor sequence such that
the efficiency of splicing an mRNA having said splice donor site is
between about 80-99%, and a 3' splice acceptor site, and a product
gene encoding a product of interest downstream of 3' splice
acceptor site, the selectable gene and the product gene being
controlled by the same transcriptional regulatory region (U.S. Pat.
No. 5,561,053).
[0010] In certain methods, use is made of polycistronic expression
vector constructs. An early report of use of this principle
describes a polycistronic expression vector, containing sequences
coding for both the desired protein and a selectable protein, which
coding sequences are governed by the same promoter and separated by
a translational stop and start signal codons (U.S. Pat. No.
4,965,196). In preferred embodiments in U.S. Pat. No. 4,965,196,
the selectable marker is the amplifiable DHFR gene. In a
particularly preferred embodiment of the system described in U.S.
Pat. No. 4,965,196, the sequence coding for the selectable marker
is downstream from that coding for the desired polypeptide, such
that procedures designed to select for the cells transformed by the
selectable marker will also select for particularly enhanced
production of the desired protein.
[0011] In further improvements based on the concept of
multicistronic expression vectors, bicistronic vectors have been
described for the rapid and efficient creation of stable mammalian
cell lines that express recombinant protein. These vectors contain
an internal ribosome entry site (IRES) between the upstream coding
sequence for the protein of interest and the downstream coding
sequence of the selection marker (Rees et al, 1996). Such vectors
are commercially available, for instance the pIRES1 vectors from
Clontech (CLONTECHniques, October 1996). Using such vectors for
introduction into host cells, selection of sufficient expression of
the downstream marker protein then automatically selects for high
transcription levels of the multicistronic mRNA, and hence a
strongly increased probability of high expression of the protein of
interest is envisaged using such vectors.
[0012] Preferably in such methods, the IRES used is an IRES which
gives a relatively low level of translation of the selection marker
gene, to further improve the chances of selecting for host cells
with a high expression level of the protein of interest by
selecting for expression of the selection marker protein (see e.g.
international publication WO 03/106684).
[0013] The present invention aims at providing improved means and
methods for selection of host cells expressing high levels of
proteins of interest.
BRIEF SUMMARY OF THE INVENTION
[0014] The present invention uses a novel and unique concept for
selecting host cells expressing high levels of polypeptides of
interest, the concept referred to herein as `reciprocal
interdependent translation`. It is unique with respect to the prior
art approaches in that an extra level of regulation is used to
fine-tune the amount of translation products from a multicistronic
transcript, whereby the level of translation of a selectable marker
polypeptide is lowered, thereby increasing the level of translation
of the polypeptide of interest coded on the same multicistronic
transcription unit, i.e. the expression level of the polypeptide of
interest is directly and more or less reciprocally dependent from
the expression level of the selectable marker polypeptide (see FIG.
13 for a schematic view). In contrast, approaches using an IRES
between the coding sequences for the polypeptide of interest and
the selectable marker polypeptide (e.g. Rees et al, 1996), involve
independent translation of both polypeptides, so that in those
approaches there is no direct effect of the translation efficiency
of the selectable marker polypeptide on that of the sequence coding
for the polypeptide of interest.
[0015] In one aspect, the invention provides a DNA molecule
comprising a multicistronic transcription unit coding for i) a
selectable marker polypeptide functional in a eukaryotic host cell,
and for ii) a polypeptide of interest, the polypeptide of interest
having a translation initiation sequence (and startcodon) separate
from that of the selectable marker polypeptide, characterized in
that the coding sequence for the polypeptide of interest is
downstream from the coding sequence for the selectable marker in
said multicistronic transcription unit, and in that the nucleic
acid sequence coding for the selectable marker polypeptide
comprises a mutation that decreases the translation efficiency of
the selectable marker in a eukaryotic host cell. Preferably the
translation initiation efficiency of the selectable marker is
decreased. In a preferred embodiment, the decreased translation
initiation efficiency is brought about by having a non-optimal
translation start sequence of the selectable marker
polypeptide.
[0016] In preferred embodiments thereof, the translation start
sequence in the coding strand for the selectable marker polypeptide
comprises an ATG sequence defining a startcodon, said ATG sequence
being in a non-optimal context for translation initiation. This
results in a decreased use of this ATG as startcodon, when compared
to an ATG startcodon in an optimal context.
[0017] In a more preferred embodiment, the translation start
sequence in the coding strand for the selectable marker polypeptide
comprises a startcodon different from an ATG startcodon, such as
one of GTG, TTG, CTG, ATT, or ACG sequence, the first two thereof
being the most preferred. Such non-ATG startcodons preferably are
flanked by sequences providing for relatively good recognition of
the non-ATG sequences as startcodons, such that at least some
ribosomes start translation from these startcodons, i.e. the
translation start sequence preferably comprises the sequence
ACC[non-ATG startcodon]G or GCC[non-ATG startcodon]G.
[0018] In preferred embodiments, the sequence encoding the
selectable marker polypeptide has no ATG sequence in the coding
strand following the sequence coding for the startcodon of the
selectable marker polypeptide up to the sequence encoding the
stopcodon thereof, and not in any sequences in the same strand
between said stopcodon and the startcodon of the polypeptide of
interest (which startcodon preferably is defined by an ATG in the
same coding strand).
[0019] In certain embodiments thereof, any ATG sequence present in
frame and coding for methionine in the sequence coding for the
wild-type selectable marker polypeptide has been mutated to code
for valine, threonine, isoleucine or leucine.
[0020] In preferred embodiments, the selectable marker protein
provides resistance against lethal and/or growth-inhibitory effects
of a selection agent, such as an antibiotic.
[0021] Preferably, the coding sequence of the polypeptide of
interest comprises an optimal translation start sequence.
[0022] The invention further provides expression cassettes
comprising a DNA molecule according to the invention, which
expression cassettes further comprise a promoter upstream of the
multicistronic expression unit and being functional in a eukaryotic
host cell for initiation transcription of the multicistronic
expression unit, and said expression cassettes further comprising a
transcription termination sequence downstream of the multicistronic
expression unit.
[0023] In preferred embodiments thereof, such expression cassettes
further comprise at least one chromatin control element chosen from
the group consisting of a matrix or scaffold attachment region
(MAR/SAR), an insulator sequence, a ubiquitous chromatin opener
element (UCOE), and an anti-repressor sequence. Anti-repressor
sequences are most preferred in this aspect, and in preferred
embodiments said anti-repressor sequences are chosen from the group
consisting of: a) any one SEQ. ID. NO. 1 through SEQ. ID. NO. 66;
b) fragments of any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 66,
wherein said fragments have anti-repressor activity; c) sequences
that are at least 70% identical in nucleotide sequence to a) or b)
wherein said sequences have anti-repressor activity; and d) the
complement to any one of a) to c). In certain preferred
embodiments, said anti-repressor sequences are chosen from the
group consisting of: STAR67 (SEQ. ID. NO. 66), STAR7 (SEQ. ID. NO.
7), STAR9 (SEQ. ID. NO. 9), STAR17 (SEQ. ID. NO. 17), STAR27 (SEQ.
ID. NO. 27), STAR29 (SEQ. ID. NO. 29), STAR43 (SEQ. ID. NO. 43),
STAR44 (SEQ. ID. NO. 44), STAR45 (SEQ. ID. NO. 45), STAR47 (SEQ.
ID. NO. 47), STAR61 (SEQ. ID. NO. 61), and functional fragments or
derivatives of these STAR sequences. In certain embodiments, the
expression cassette comprises STAR67, or a functional fragment or
derivative thereof, positioned upstream of the promoter driving
expression of the multicistronic gene. In certain embodiments, the
multicistronic gene is flanked on both sides by at least one
anti-repressor sequence. In certain preferred embodiments,
expression cassettes are provided according to the invention,
comprising in 5' to 3' order: anti-repressor sequence
A--anti-repressor sequence B--[promoter--multicistronic
transcription unit according to the invention (encoding the
functional selectable marker protein and downstream thereof the
polypeptide of interest)--transcription termination
sequence]--anti-repressor sequence C, wherein A, B and C may be the
same or different.
[0024] In certain embodiments, the polypeptide of interest is a
part of a multimeric protein, for example a heavy or light chain of
an immunoglobulin.
[0025] The invention also provides DNA molecules comprising a
sequence encoding a functional selectable marker polypeptide,
characterized in that such DNA molecules comprise a mutation that
decreases the translation efficiency of the functional selectable
marker polypeptide in a eukaryotic host cell. Preferably, such a
DNA molecule: i) has a non-optimal translation start sequence
followed by an otherwise functional selectable marker coding
sequence, and ii) in the coding strand of the sequence defining the
selectable marker polypeptide downstream of the non-optimal
startcodon is devoid of ATG sequences.
[0026] The invention also provides host cells comprising DNA
molecules according to the invention.
[0027] The invention further provides methods for generating host
cells expressing a polypeptide of interest, the method comprising
the steps of: introducing into a plurality of precursor host cells
an expression cassette according to the invention, culturing the
cells under conditions selecting for expression of the selectable
marker polypeptide, and selecting at least one host cell producing
the polypeptide of interest.
[0028] In a further aspect, the invention provides methods for
producing a polypeptide of interest, the methods comprising
culturing a host cell, said host cell comprising an expression
cassette according to the invention, and expressing the polypeptide
of interest from the expression cassette. In preferred embodiments
thereof, the polypeptide of interest is further isolated from the
host cells and/or from the host cell culture medium.
[0029] In further aspects, the invention provides RNA molecules
having the sequence of a transcription product of a DNA molecule
according to the invention.
[0030] In another aspect, the invention provides functional
selectable marker polypeptides lacking methionine in their amino
acid sequence, which polypeptides are obtainable by expression from
certain DNA molecules according to the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0031] FIG. 1. Schematic diagram of transcription units without and
with STAR elements. A) bicistronic gene containing (from 5' to 3')
a transgene (encoding for example the d2EGFP gene), an IRES, and a
selectable marker (zeo, conferring zeocin resistance) under control
of the CMV promoter. The expression unit has the SV40
transcriptional terminator at its 3' end (t). The name of the
construct is CMV-d2EGFP-ires-Zeo (CMV Control). B) construct as in
A, but now STAR 67 is cloned upstream of the CMV promoter. The name
of the construct is STAR67-CMV-d2EGFP-ires-Zeo (CMV-STAR67). C)
construct as in B, but upstream and downstream STAR7 elements are
cloned to flank the entire construct. The name of the construct is
STAR7-STAR67-CMV-d2EGFP-ires-Zeo-STAR7 (CMV-STAR67 7/7)
[0032] FIG. 2. STAR67 improves CMV driven d2EGFP expression in CHO
cells. The mean of the d2EGFP signal for 10 independent stable
colonies is plotted for the indicated constructs in CHO cells. A)
CMV Control; B) STAR67-CMV. X(10): average d2EGFP expression levels
of the 10 colonies. See example 2 for details.
[0033] FIG. 3. STAR67 improves EF1.alpha. driven d2EGFP expression
in CHO cells. Same as FIG. 2, but now with EF1.alpha. promoter. A)
EF1.alpha. Control; B) STAR67-EF1.alpha..
[0034] FIG. 4. STAR67 improves UB6 driven d2EGFP expression in CHO
cells. Same as FIGS. 2 and 3, but now with UB6 promoter. A) UB6
Control; B) STAR67-UB6.
[0035] FIG. 5. STAR67 improves CMV driven d2EGFP expression in
PER.C6 cells. Same as FIG. 2, but now in PER.C6 cells. A) CMV
Control; B) STAR67-CMV.
[0036] FIG. 6. STAR67 improves EF1.alpha. driven d2EGFP expression
in PER.C6 cells. Same as FIG. 3, but now in PER.C6 cells. A)
EF1.alpha. Control; B) STAR67-EF1.alpha..
[0037] FIG. 7. STAR67 improves UB6 driven d2EGFP expression in
PER.C6 cells. Same as FIG. 4, but now in PER.C6 cells. A) UB6
Control; B) STAR67-UB6.
[0038] FIG. 8. STAR67 improves SV40 driven d2EGFP expression in
CHO-K1 cells in combination with another STAR element. Similar as
FIG. 2, but now using the SV40 promoter in CHO cells, and the
indicated constructs. The mean of the d2EGFP signal is plotted for
18-20 independent stable colonies 60 days after transfection. A)
SV40 Control, SV40-STAR67, SV40-STAR7/7; B) SV40 Control and
SV40-STAR67 7/7. See example 4 for details.
[0039] FIG. 9. STAR67 improves UB6 driven expression levels of the
EpCAM antibody in CHO-K1 cells. See example 5 for details. A)
constructs without STAR elements; B) constructs with STAR67
upstream of promoter and flanking STAR7 elements. The anti-EpCAM
antibody concentration is presented as pg/cell/day. X(18): average
production level of the 18 colonies.
[0040] FIG. 10. STAR67 is not an enhancer blocker, whereas STAR 6
and 7 are. See example 6 for details.
[0041] FIG. 11. STAR67 enhances UB6 and CMV-driven antibody
expression levels in stably transfected CHO cells. See example 7
for details. A) single DNA molecule containing anti-EpCAM heavy
chain (HC) and light chain (LC), each behind a promoter, and each
linked to a different selectable marker gene (simultaneous
selection was used for both markers): construct without STAR
elements. No colonies were found; B) same construct with STAR67
between the two promoters. The anti-EpCAM antibody concentration is
presented as pg/cell/day. X(19): average production level of the 19
colonies.
[0042] FIG. 12. Schematic representation of the use of a selection
marker gene (zeocin resistance gene) according to the invention. A.
wild-type zeocin resitance gene, having its normal translation
initation site (ATG startcodon) and one internal ATG codon, which
codes for methionine. B. mutant zeocin resistance gene, wherein the
internal ATG has been mutated into a codon for leucine; this mutant
is a functional zeocin resistance gene. C. same as B, but
comprising a mutated translation initiation site, wherein the
context of the ATG startcodon has been mutated to decrease the
translation initiation. D. same as B, but comprising a mutated
startcodon (GTG). E. same as B, but with a TTG startcodon. The
numbers under the figures C-E schematically indicate a relative
amount of initiation frequency (under the startcodon) and
`scan-through` frequency (under the coding sequence) by the
ribosomes, but only in a semi-quantitative manner, i.e. they
indicate the efficiency of translation initiation compared to each
other, but the qualitative numbers may differ completely: the
numbers only serve to explain the invention. See example 8 for
details.
[0043] FIG. 13. Schematic representation of a multicistronic
transcription unit according to the invention, with more or less
reciprocal interdependent translation efficiency. Explanation as
for FIG. 12, but now a dEGFP gene (here exemplifying a gene of
interest) has been placed downstream of the selectable marker
polypeptide coding sequence. The Zeocin resistance gene comprises
the internal Met.fwdarw.Leu mutation (see FIG. 12B). See example 9
for details.
[0044] FIG. 14. Results of selection systems according to the
invention, with and without STAR elements. A. zeocin resistance
gene with ATG startcodon in bad context (referred to as "ATGmut" in
the picture, but including a spacer sequence behind the ATG in the
bad context, so in the text generally referred to as
"ATGmut/space"). B. zeocin resistance gene with GTG startcodon. C.
zeocin resistance gene with TTG startcodon. d2EGFP signal for
independent colonies is shown on the vertical axis. See example 9
for details.
[0045] FIG. 15. Results of selection system according to the
invention in upscaled experiment (A), and comparison with selection
system according to prior art using an IRES (B). d2EGFP signal for
independent colonies is shown on the vertical axis. See example 10
for details.
[0046] FIG. 16. Results of selection system with multicistronic
transcription unit according to the invention, using blasticidin as
a selectable marker. A. blasticidin resistance gene mutated to
comprise a GTG startcodon. B. blasticidin resistance gene mutated
to comprise a TTG startcodon. The blasticidin resistance gene has
further been mutated to remove all internal ATG sequences. d2EGFP
signal for independent colonies is shown on the vertical axis. See
example 11 for details.
[0047] FIG. 17. Stability of expression of several clones with a
multicistronic transcription unit according to the invention
(including a zeocin with TTG startcodon). Selection pressure (100
.mu.g/ml zeocin) was present during the complete experiment. d2EGFP
signal for independent colonies is shown on the vertical axis. See
example 12 for details.
[0048] FIG. 18. As FIG. 17, but zeocin concentration was lowered to
20 .mu.g/ml after establishment of clones.
[0049] FIG. 19. As FIG. 17, but zeocin was absent from culture
medium after establishment of clones.
[0050] FIG. 20. Expression of an antibody (anti-EpCAM) using the
selection system with the multicistronic transcription unit
according to the invention. The heavy chain (HC) and light chain
(LC) are the polypeptide of interest in this example. Each of these
is present in a separate transcription unit, which are both on a
single nucleic acid molecule in this example. The HC is preceded by
the zeocin resistance gene coding for a selectable marker
polypeptide, while the LC is preceded by the blasticidin resistance
gene coding for a selectable marker polypeptide. Both resistance
genes have been mutated to comprise an ATG startcodon in a
non-optimal context ("mutATG" in Figure, but including a spacer
sequence, and hence in the text generally referred to as
"ATGmut/space"). Each of the multicistronic transcription units is
under control of a CMV promoter. Constructs with STAR sequences as
indicated were compared to constructs without STAR sequences. The
antibody levels obtained when these constructs were introduced into
host cells are given on the vertical axis in pg/cell/day for
various independent clones. See example 13 for details.
[0051] FIG. 21. As FIG. 20, but both the selection marker genes
have been provided with a GTG startcodon. See example 13 for
details.
[0052] FIG. 22. As FIG. 20, but both the selection marker genes
have been provided with a TTG startcodon. See example 13 for
details.
[0053] FIG. 23. Stability of expression in sub-clones in the
absence of selection pressure (after establishing colonies under
selection pressure, some colonies where sub-cloned in medium
containing no zeocin). See example 12 for details.
[0054] FIG. 24. Copy-number dependency of expression levels of an
embodiment of the invention. See example 12 for details.
[0055] FIG. 25. As FIG. 12, but for the blasticidin resistance
gene. None of the 4 internal ATG's in this gene are in frame coding
for a methionine, and therefore the redundancy of the genetic code
was used to mutate these ATG's without mutating the internal amino
acid sequence of the encoded protein.
[0056] FIG. 26. Coding sequence of the wild-type zeocin resistance
gene (SEQ. ID. NO. 108). Bold ATG's code for methione. The first
bold ATG is the startcodon.
[0057] FIG. 27. Coding sequence of the wild-type blasticidin
resistance gene (SEQ. ID. NO. 110). Bold ATG's code for methione.
The first bold ATG is the startcodon. Other ATG's in the sequence
are underlined: these internal ATG's do not code for methionine,
because they are not in frame.
[0058] FIG. 28. Coding sequence of the wild-type puromycin
resistance gene (SEQ. ID. NO. 112). Bold ATG's code for methione.
The first bold ATG is the startcodon.
[0059] FIG. 29. Coding sequence of the wild-type mouse DHFR gene
(SEQ. ID. NO. 114). Bold ATG's code for methione. The first bold
ATG is the startcodon. Other ATG's in the sequence are underlined:
these internal ATG's do not code for methionine, because they are
not in frame.
[0060] FIG. 30. Coding sequence of the wild-type hygromycin
resistance gene (SEQ. ID. NO. 116). Bold ATG's code for methione.
The first bold ATG is the startcodon. Other ATG's in the sequence
are underlined: these internal ATG's do not code for methionine,
because they are not in frame.
[0061] FIG. 31. Coding sequence of the wild-type neomycin
resistance gene (SEQ. ID. NO. 118). Bold ATG's code for methione.
The first bold ATG is the startcodon. Other ATG's in the sequence
are underlined: these internal ATG's do not code for methionine,
because they are not in frame.
[0062] FIG. 32. Coding sequence of the wild-type human glutamine
synthase (GS) gene (SEQ. ID. NO. 120). Bold ATG's code for
methione. The first bold ATG is the startcodon. Other ATG's in the
sequence are underlined: these internal ATG's do not code for
methionine, because they are not in frame.
[0063] FIG. 33. Schematic representation of some further modified
zeocin resistance selection marker genes with a GTG startcodon
according to the invention, allowing for further fine-tuning of the
selection stringency. See example 14 for details.
[0064] FIG. 34. Results with expression systems containing the
further modified zeocin resistance selection marker genes. See
example 14 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs (see also
FIG. 33) are indicated on the horizontal axis (the addition of
7/67/7 at the end of the construct name indicates the presence of
STAR sequences 7 and 67 upstream of the promoter and STAR7
downstream of the transcription termination site), and
schematically depicted above the graph; vertical axis indicates
d2EGFP signal.
[0065] FIG. 35. Schematic representation of some further modified
zeocin resistance selection marker genes with a TTG startcodon
according to the invention, allowing for further fine-tuning of the
selection stringency. See example 15 for details.
[0066] FIG. 36. Results with expression systems containing the
further modified zeocin resistance selection marker genes. See
example 15 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs are
indicated on the horizontal axis, and schematically depicted above
the graph; vertical axis indicates d2EGFP signal.
[0067] FIG. 37. As FIG. 12, but for the puromycin resistance gene.
All three internal ATG's code for methione (panel A), and are
replaced by CTG sequences coding for leucine (panel B). See example
16 for details.
[0068] FIG. 38. Results with expression constructs containing the
puromycin resistance gene with a TTG startcodon and no internal ATG
codons. See example 16 for details. Dots indicate individual data
points; lines indicate the average expression levels; used
constructs are indicated on the horizontal axis, and schematically
depicted above the graph; vertical axis indicates d2EGFP
signal.
[0069] FIG. 39. As FIG. 12, but for the neomycin resistance gene.
See Example 17 for details. A. wild-type neomycin resistance gene;
ATG sequences are indicated, ATGs coding for methionine are
indicated by Met above the ATG. B. neomycin resistance gene without
ATG sequences, and with a GTG startcodon. C. neomycin resistance
gene without ATG sequences, and with a TTG startcodon.
[0070] FIG. 40. As FIG. 12, but for the dhfr gene. See Example 18
for details. A. wild-type dhfr gene; ATG sequences are indicated,
ATGs coding for methionine are indicated by Met above the ATG. B.
dhfr gene without ATG sequences, and with a GTG startcodon. C. dhfr
gene without ATG sequences, and with a TTG startcodon.
[0071] FIG. 41. Results with expression constructs (zeocin
selectable marker) according to the invention in PER.C6 cells. See
Example 20 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs are
indicated on the horizontal axis, and schematically depicted above
the graph; vertical axis indicates d2EGFP signal.
[0072] FIG. 42. Results with expression constructs (blasticidin
selectable marker) according to the invention in PER.C6 cells. See
Example 20 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs are
indicated on the horizontal axis, and schematically depicted above
the graph; vertical axis indicates d2EGFP signal.
[0073] FIG. 43. Results with expression constructs according to the
invention, further comprising a transcription pause (TRAP)
sequence. See Example 21 for details. Dots indicate individual data
points; lines indicate the average expression levels; used
constructs are indicated on the horizontal axis, and schematically
depicted above the graph; vertical axis indicates d2EGFP
signal.
[0074] FIG. 44. Copy-number dependency of expression of an antibody
using transcription units according to the invention. See Example
22 for details.
[0075] FIG. 45. Antibody expression from colonies containing
expression constructs according to the invention, wherein the copy
number of the expression constructs is amplified by methotrexate.
See Example 23 for details. White bars: selection with zeocin and
blasticidin; black bars: selection with zeocin, blasticidin and
methotrexate (MTX). Numbers of tested colonies are depicted on the
horizontal axis.
[0076] FIG. 46. Results with different promoters. See Example 24
for details. Dots indicate individual data points; lines indicate
the average expression levels; used constructs are indicated on the
horizontal axis, and schematically depicted above the graph;
vertical axis indicates d2EGFP signal.
[0077] FIG. 47. Results with different STAR elements. See example
25 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs are
indicated on the horizontal axis, and schematically depicted above
the graph; vertical axis indicates d2EGFP signal.
[0078] FIG. 48. Results with other chromatin control elements. See
Example 26 for details. Dots indicate individual data points; lines
indicate the average expression levels; used constructs are
indicated on the horizontal axis, and schematically depicted above
the graph (black triangles indicate different tested chromatin
control elements); vertical axis indicates d2EGFP signal.
DETAILED DESCRIPTION OF THE INVENTION
[0079] In one aspect, the invention provides a DNA molecule
comprising a multicistronic transcription unit coding for i) a
selectable marker polypeptide functional in a eukaryotic host cell,
and for ii) a polypeptide of interest, the polypeptide of interest
having a translation initiation sequence separate from that of the
selectable marker polypeptide, characterized in that the coding
sequence for the polypeptide of interest is downstream from the
coding sequence for the selectable marker in said multicistronic
transcription unit, and the nucleic acid sequence coding for the
selectable marker polypeptide comprises a mutation that decreases
the translation efficiency of the selectable marker in a eukaryotic
host cell. Such a DNA molecule can be used according to the
invention for obtaining eukaryotic host cells expressing high
levels of the polypeptide of interest, by selecting for the
expression of the selectable marker polypeptide. Subsequently or
simultaneously, one or more host cell(s) expressing the polypeptide
of interest can be identified, and further used for expression of
high levels of the polypeptide of interest.
[0080] The term "monocistronic gene" is defined as a gene capable
of providing a RNA molecule that encodes one polypeptide. A
"multicistronic transcription unit", also referred to as
multicistronic gene, is defined as a gene capable of providing an
RNA molecule that encodes at least two polypeptides. The term
"bicistronic gene" is defined as a gene capable of providing a RNA
molecule that encodes two polypeptides. A bicistronic gene is
therefore encompassed within the definition of a multicistronic
gene. A "polypeptide" as used herein comprises at least five amino
acids linked by peptide bonds, and can for instance be a protein or
a part, such as a subunit, thereof. Mostly, the terms polypeptide
and protein are used interchangeably herein. A "gene" or a
"transcription unit" as used in the present invention can comprise
chromosomal DNA, cDNA, artificial DNA, combinations thereof, and
the like. Transcription units comprising several cistrons are
transcribed as a single mRNA. In contrast to approaches used in the
prior art, in the multicistronic transcription units of the
invention, translation of the second coding region (i.e. that for
the protein of interest) present on that RNA is not dependent on
the use of translation reinitiation sites or internal ribosome
entry sites for translation iniation of the second coding region,
but rather it is dependent on the efficiency of translation of the
first coding region (i.e. that for the selectable marker protein)
in a more or less reciprocal manner: the higher the translation
level of the selectable marker, the lower the transcription level
of the protein of interest and vice versa.
[0081] A multicistronic transcription unit according to the
invention preferably is a bicistronic transcription unit coding
from 5' to 3' for a selectable marker polypeptide and a polypeptide
of interest. Hence, the polypeptide of interest is encoded
downstream from the coding sequence for the selectable marker
polypeptide.
[0082] It is also possible to include more coding sequences on the
same transcription unit, downstream of the (first) polypeptide of
interest, e.g. coding for a second selectable marker polypeptide or
for a second polypeptide of interest. Such an extra coding sequence
downstream of the coding sequence for the first polypeptide of
interest then preferably is preceded by a sequence encoding a
translation reinitiation site or internal ribosome entry site
(IRES), such that also the second polypeptide of interest or the
second selection marker polypeptide is translated, in this case
independently from the earlier two coding sequences. In such an
embodiment, it is for instance possible to have the coding
sequences for subunits of a multimeric protein, e.g. a heavy and a
light chain of an immunoglobulin, encoded as a first and second
polypeptide of interest (in any order), to code for subunits of a
multimeric protein within a single multicistronic expression unit.
It is however preferred to use separate transcription units for the
expression of different polypeptides of interest, also when these
form part of a multimeric protein (see e.g. example 13: the heavy
and light chain of an antibody each are encoded by a separate
transcription unit, each of these expression units being a
bicistronic expression unit according to the invention).
[0083] The DNA molecules of the invention can be present in the
form of double stranded DNA, having with respect to the selectable
marker polypeptide and the polypeptide of interest a coding strand
and a non-coding strand, the coding strand being the strand with
the same sequence as the translated RNA, except for the presence of
T instead of U. Hence, an AUG startcodon is coded for in the coding
strand by an ATG sequence, and the strand containing this ATG
sequence corresponding to the AUG startcodon in the RNA is referred
to as the coding strand of the DNA. It will be clear to the skilled
person that startcodons or translation initiation sequences are in
fact present in an RNA molecule, but that these can be considered
equally embodied in a DNA molecule coding for such an RNA molecule;
hence, wherever the present invention refers to a startcodon or
translation initation sequence, the corresponding DNA molecule
having the same sequence as the RNA sequence but for the presence
of a T instead of a U in the coding strand of said DNA molecule is
meant to be included, and vice versa, except where explicitly
specified otherwise. In other words, a startcodon is for instance
an AUG sequence in RNA, but the corresponding ATG sequence in the
coding strand of the DNA is referred to as startcodon as well in
the present invention. The same is used for the reference of `in
frame` coding sequences, meaning triplets (3 bases) in the RNA
molecule that are translated into an amino acid, but also to be
interpreted as the corresponding trinucleotide sequences in the
coding strand of the DNA molecule.
[0084] The selectable marker polypeptide and the polypeptide of
interest encoded by the multicistronic gene each have their own
translation initation sequence, and therefore each have their own
startcodon (as well as stopcodon), i.e. they are encoded by
separate open reading frames.
[0085] The term "selection marker" or "selectable marker" is
typically used to refer to a gene and/or protein whose presence can
be detected directly or indirectly in a cell, for example a
polypeptide that inactivates a selection agent and protects the
host cell from the agent's lethal or growth-inhibitory effects
(e.g. an antibiotic resistance gene and/or protein). Another
possibility is that said selection marker induces fluorescence or a
color deposit (e.g. green fluorescent protein (GFP) and derivatives
(e.g d2EGFP), luciferase, lacZ, alkaline phosphatase, etc.), which
can be used for selecting cells expressing the polypeptide inducing
the color deposit, e.g. using a fluorescence activated cell sorter
(FACS) for selecting cells that express GFP. Preferably, the
selectable marker polypeptide according to the invention provides
resistance against lethal and/or growth-inhibitory effects of a
selection agent. The selectable marker polypeptide is encoded by
the DNA of the invention. The selectable marker polypeptide
according to the invention must be functional in a eukaryotic host
cell, and hence being capable of being selected for in eukaryotic
host cells. Any selectable marker polypeptide fulfilling this
criterion can in principle be used according to the present
invention. Such selectable marker polypeptides are well known in
the art and routinely used when eukaryotic host cell clones are to
be obtained, and several examples are provided herein. In certain
embodiments, a selection marker used for the invention is zeocin.
In other embodiments, blasticidin is used. The person skilled in
the art will know that other selection markers are available and
can be used, e.g. neomycin, puromycin, bleomycin, hygromycin, etc.
In other embodiments, kanamycin is used. In yet other embodiments,
the DHFR gene is used as a selectable marker, which can be selected
for by methotrexate, especially by increasing the concentration of
methotrexate cells can be selected for increased copy numbers of
the DHFR gene. Similarly, the glutamine synthetase (GS) gene can be
used, for which selection is possible in cells having insufficient
GS (e.g. NS-0 cells) by culturing in media without glutamine, or
alternatively in cells having sufficient GS (e.g. CHO cells) by
adding an inhibitor of GS, methionine sulphoximine (MSX). Other
selectable marker genes that could be used, and their selection
agents, are for instance described in table 1 of U.S. Pat. No.
5,561,053, incorporated by reference herein; see also Kaufman,
Methods in Enzymology, 185:537-566 (1990), for a review of
these.
[0086] When two multicistronic transcription units are to be
selected for according to the invention in a single host cell, each
one preferably contains the coding sequence for a different
selectable marker, to allow selection for both multicistronic
transcription units. Of course, both multicistronic transcription
units may be present on a single nucleic acid molecule or
alternatively each one may be present on a separate nucleic acid
molecule.
[0087] The term "selection" is typically defined as the process of
using a selection marker/selectable marker and a selection agent to
identify host cells with specific genetic properties (e.g. that the
host cell contains a transgene integrated into its genome). It is
clear to a person skilled in the art that numerous combinations of
selection markers are possible. One antibiotic that is particularly
advantageous is zeocin, because the zeocin-resistance protein
(zeocin-R) acts by binding the drug and rendering it harmless.
Therefore it is easy to titrate the amount of drug that kills cells
with low levels of zeocin-R expression, while allowing the
high-expressors to survive. All other antibiotic-resistance
proteins in common use are enzymes, and thus act catalytically (not
1:1 with the drug). Hence, the antibiotic zeocin is a preferred
selection marker. However, the invention also works with other
selection markers.
[0088] A selectable marker polypeptide according to the invention
is the protein that is encoded by the nucleic acid of the
invention, which polypeptide can be detected, for instance because
it provides resistance to a selection agent such as an antibiotic.
Hence, when an antibiotic is used as a selection agent, the DNA
encodes a polypeptide that confers resistance to the selection
agent, which polypeptide is the selectable marker polypeptide. DNA
sequences coding for such selectable marker polypeptides are known,
and several examples of wild-type sequences of DNA encoding
selectable marker proteins are provided herein (FIGS. 26-32). It
will be clear that mutants or derivatives of selectable markers can
also be suitably used according to the invention, and are therefore
included within the scope of the term `selectable marker
polypeptide`, as long as the selectable marker protein is still
functional.
[0089] For convenience and as generally accepted by the skilled
person, in many publications as well as herein, often the gene and
protein encoding the resistance to a selection agent is referred to
as the `selectable agent (resistance) gene` or `selection agent
(resistance) protein`, respectively, although the official names
may be different, e.g. the gene coding for the protein conferring
restance to neomycin (as well as to G418 and kanamycin) is often
referred to as neomycin (resistance) (or neo.sup.r) gene, while the
official name is aminoglycoside 3'-phosphotransferase gene.
[0090] For the present invention, it is beneficial to have low
levels of expression of the selectable marker polypeptide, so that
stringent selection is possible. In the present invention this is
brought about by using a selectable marker coding sequence with a
non-optimal translation efficiency. Upon selection, only cells that
have nevertheless sufficient levels of selectable marker
polypeptide will be selected, meaning that such cells must have
sufficient transcription of the multicistronic transcription unit
and sufficient translation of the selectable marker polypeptide,
which provides a selection for cells where the multicistronic
transcription unit has been integrated or otherwise present in the
host cells at a place where expression levels from this
transcription unit are high. According to the invention the (more
or less) reciprocally interdependent nature of the translation of
the polypeptide of interest from that of the translation efficiency
of the marker, ensures high translation levels of the polypeptide
of interest. This high level of translation is superimposed on the
high transcription levels selected for by the stringent selection
conditions (and resulting from the use of a strong promoter in the
host cells to drive transcription of the multicistronic
transcription unit).
[0091] The DNA molecules according to the invention have the coding
sequence for the selectable marker polypeptide upstream of the
coding sequence for the polypeptide of interest, to provide for a
multicistronic transcript with reciprocally interdependent
translation of the polypeptide of interest and the selectable
marker polypeptide. Hence, the multicistronic transcription unit
comprises in the 5' to 3' direction (both in the transcribed strand
of the DNA and in the resulting transcribed RNA) the coding
sequence for the selectable marker polypeptide and the sequence
encoding the polypeptide of interest.
[0092] According to the invention, the coding regions of the
multicistronic gene are preferably translated from the
cap-dependent ORF, and therefore the selectable marker polypeptide
would in principle also be produced in abundance. To prevent such
high translation of the selectable marker cistron, according to the
invention the nucleic acid sequence coding for the selectable
marker polypeptide comprises a mutation (within the open reading
frame (ORF) or in the translation initiation sequences preceding
the ORF, or in both) that decreases the translation efficiency of
the selectable marker polypeptide in a eukaryotic host cell. The
translation efficiency should be lower than that of the
corresponding wild-type sequence in the same cell, i.e. the
mutation should result in less polypeptide per cell per time unit,
and hence less selectable marker polypeptide. This can be detected
using routine methods known to the person skilled in the art. For
instance in the case of antibiotic selection the mutation will
result in less resistance than obtained with the sequence having no
such mutation and hence normal translation efficiency, which
difference can easily be detected by determining the number of
surviving colonies after a normal selection period, which will be
lower when a translation efficiency decreasing mutation is present.
As is well known to the person skilled in the art there are a
number of parameters that indicate the expression level marker
polypeptide such as, the maximum concentration of selection agent
to which cells are still resistant, number of surviving colonies at
a given concentration, growth speed (doubling time) of the cells in
the presence of selection agent, combinations of the above, and the
like.
[0093] In a particularly preferred embodiment, the mutation that
decreases the translation efficiency, is a mutation that decreases
the translation initiation efficiency.
[0094] This can for example be established according to the
invention by providing the selectable marker polypeptide coding
sequence with a non-optimal translation start sequence.
[0095] For example, the translation initiation efficiency of the
selectable marker gene in eukaryotic cells can be suitably
decreased according to the invention by mutating the startcodon
and/or the nucleotides in positions -3 to -1 and +4 (where the A of
the ATG startcodon is nt +1), for instance in the coding strand of
the corresponding DNA sequence, to provide a non-optimal
translation start sequence. A translation start sequence is often
referred to in the field as `Kozak sequence`, and an optimal Kozak
sequence is RCCATGG, the startcodon underlined, R being a purine,
i.e. A or G (see Kozak M, 1986, 1987, 1989, 1990, 1997, 2002).
Hence, besides the startcodon itself, the context thereof, in
particular nucleotides -3 to -1 and +4, are relevant, and an
optimal translation startsequence comprises an optimal startcodon
(i.e. ATG) in an optimal context (i.e. the ATG directly preceded by
RCC and directly followed by G). A non-optimal translation start
sequence is defined herein as any sequence that gives at least some
detectable translation in a eukaryotic cell (detectable because the
selection marker polypeptide is detectable), and not having the
consensus sequence RCCATGG (startcodon underlined). Translation by
the ribosomes starts preferably at the first startcodon it
encounters when scanning from the 5'-cap of the mRNA (scanning
mechanism), and is most efficient when an optimal Kozak sequence is
present (see Kozak M, 1986, 1987, 1989, 1990, 1997, 2002). However,
in a small percentage of events, non-optimal translation initiation
sequences are recognized and used by the ribosome to start
translation. The present invention makes use of this principle, and
allows for decreasing and even fine-tuning of the amount of
translation and hence expression of the selectable marker
polypeptide, which can therefore be used to increase the stringency
of the selection system.
[0096] In a first embodiment of the invention, the ATG startcodon
of the selectable marker polypeptide (in the coding strand of the
DNA, coding for the corresponding AUG startcodon in the RNA
transcription product) is left intact, but the positions at -3 to
-1 and +4 are mutated such that they do not fulfill the optimal
Kozak sequence any more, e.g. by providing the sequence TTTATGT as
the translation start site (ATG startcodon underlined). It will be
clear that other mutations around the startcodon at positions -3 to
-1 and/or +4 could be used with similar results using the teaching
of the present invention, as can be routinely and easily tested by
the person skilled in the art. The idea of this first embodiment is
that the ATG startcodon is placed in a `non-optimal` context for
translation initiation.
[0097] In a second and preferred embodiment, the ATG startcodon
itself of the selectable marker polypeptide is mutated. This will
in general lead to even lower levels of translation initiation than
the first embodiment. The ATG startcodon in the second embodiment
is mutated into another codon, which has been reported to provide
some translation initiation, for instance to GTG, TTG, CTG, ATT, or
ACG (collectively referred to herein as `non-optimal start
codons`). In preferred embodiments, the ATG startcodon is mutated
into a GTG startcodon. This provides still lower expression levels
(lower translation) than with the ATG startcodon intact but in a
non-optimal context. More preferably, the ATG startcodon is mutated
to a TTG startcodon, which provides even lower expression levels of
the selectable marker polypeptide than with the GTG startcodon
(Kozak M, 1986, 1987, 1989, 1990, 1997, 2002; see also examples
9-13 herein).
[0098] For the second embodiment, i.e. where a non-ATG startcodon
is used, it is strongly preferred to provide an optimal context for
such a startcodon, i.e. the non-optimal startcodons are preferably
directly preceded by nucleotides RCC in positions -3 to -1 and
directly followed by a G nucleotide (position +4). However, it has
been reported that using the sequence TTTGTGG (startcodon
underlined), some initiation is observed at least in vitro, so
although strongly preferred it may not be absolutely required to
provide an optimal context for the non-optimal startcodons.
[0099] ATG sequences within the coding sequence for a polypeptide,
but excluding the ATG startcodon, are referred to as `internal
ATGs`, and if these are in frame with the ORF and therefore code
for methionine, the resulting methionine in the polypeptide is
referred to as an `internal methionine`. It is strongly preferred
according to the invention that the coding region (following the
startcodon, not necessarily including the startcodon) coding for
the selectable marker polypeptide preferably is devoid of any ATG
sequence in the coding strand of the DNA, up to (but not including)
the startcodon of the polypeptide of interest (obviously, the
startcodon of the polypeptide of interest may be, and in fact
preferably is, an ATG startcodon). This can be established by
mutating any such ATG sequence within the coding sequence of the
selectable marker polypeptide, following the startcodon thereof (as
is clear from the teaching above, the startcodon of the selectable
marker polypeptide itself may be an ATG sequence, but not
necessarily so). To this purpose preferably, the degeneracy of the
genetic code is used to avoid mutating amino acids in the
selectable marker polypeptide wherever possible. Hence, wherever an
ATG is present in the coding strand of the DNA sequence encoding
the selectable marker polypeptide, which ATG is not in frame with
the selectable marker polypeptide ORF, and therefore does not code
for an internal methionine in the selectable marker polypeptide,
the ATG can be mutated such that the resulting polypeptide has no
mutations in its internal amino acid sequence. Where the ATG is an
in-frame codon coding for an internal methionine, the codon can be
mutated, and the resulting mutated polypeptide can be routinely
checked for activity of the selectable marker polypeptide. In this
way a mutation can be chosen which leads to a mutated selectable
marker polypeptide that is still active as such (quantitative
differences may exist, but those are less relevant, and in fact it
could even be beneficial to have less active variants for the
purpose of the present invention; the minimum requirement is that
the selectable marker polypeptide can still be selected for in
eukaryotic cells). Amino acids valine, threonine, isoleucine and
leucine are structurally similar to methionine, and therefore
codons that code for one of these amino acids are good starting
candidates to be tested in place of methione within the coding
sequence after the startcodon. Of course, using the teachings of
the present invention, the skilled person may test other amino
acids as well in place of internal methionines, using routine
molecular biology techniques for mutating the coding DNA, and
routine testing for functionality of the selectable marker
polypeptide. Besides routine molecular biology techniques for
mutating DNA, it is at present also possible to synthesise at will
(if required using subcloning steps) DNA sequences that have
sufficient length for an ORF of a selectable marker polypeptide,
and such synthetic DNA sequences can nowadays be ordered
commercially from various companies. Hence, using the teachings of
the present invention, the person skilled in the art may design
appropriate sequences according to the invention encoding a
selectable marker polypeptide (with a mutation decreasing
translation initiation, and preferably having no internal ATGs),
have this sequence synthesized, and test the DNA molecule for
functionality of the encoded selectable marker by introducing the
DNA molecule in eukaryotic host cells and test for expression of
functional selectable marker polypeptide. The commercial
availability of such sequences also makes feasible to provide
without undue burden for selection marker coding sequences lacking
internal ATG sequences, where the wild-type coding sequence of the
selection marker polypeptide comprises several such internal
ATGs.
[0100] By providing a coding sequence for a selectable marker
polypeptide lacking any internal ATG sequence, the chances of
inadvertent translation initiation by ribosomes that passed the
(first, non-optimal) translation start sequence of the selectable
marker polypeptide at a subsequent internal ATG trinucleotide is
diminished, so that the ribosomes will continue to scan for the
first optimal translation start sequence, i.e. that of the
polypeptide of interest.
[0101] It will be clear that it is not necessarily strictly
required to remove all internal ATG sequences from the coding
sequence of the selectable marker, as long as the vast majority of
ribosomes will not use such internal ATG sequences as a translation
initiation start site, for instance because such internal ATGs
usually are not in an optimal context for translation initiation.
However, also in view of the fact that even an ATG sequence in a
non-optimal context gives rise to significant translation
initiation events (in general much higher than from a non-ATG
startcodon in an optimal context), it will also be clear that if
several internal ATG sequences are present in the coding region of
the selectable marker, each of these might subtract a fraction of
ribosomes that start translation at those ATGs, preventing them
from reaching the downstream translation unit encoding the
polypeptide of interest, and hence result in less expression of the
polypeptide of interest. This is the reason why it is preferred to
have a sequence encoding the selectable marker polypeptide, which
sequence is free of internal ATG sequences. Possibly, if desired,
the ratio of ribosomes translating the polypeptide of interest
might even be further enhanced by mutating any non-optimal
potential translation initiation sites within the sequence coding
for the selectable marker polypeptide.
[0102] Clearly, any sequence present in the coding strand between
the stopcodon of the selectable marker and the startcodon of the
polypeptide of interest can easily be designed such that it does
not comprise ATG sequences, or other non-optimal potential
translation start codons.
[0103] Clearly, it is strongly preferred according to the present
invention, that the translation start sequence of the polypeptide
of interest comprises an optimal translation start sequence, i.e.
having the consensus sequence RCCATGG (startcodon underlined). This
will result in a very efficient translation of the polypeptide of
interest.
[0104] As a consequence of these measures, the reciprocally
interdependent translation mechanism of the invention is provided:
ribosomes scan from the cap of the mRNA containing the
multicistronic transcription unit, and a small percentage of
ribosomes will translate the first open reading frame, i.e. the
selectable marker protein, because this is provided with a mutation
decreasing the translation efficiency, while the great majority of
the ribosomes will pass this open reading frame and start
translation at the optimal translation initiation site of the
polypeptide of interest, resulting in low levels of selectable
marker protein and high levels of polypeptide of interest. By
providing the coding sequence of the marker with different
mutations leading to several levels of decreased translation
efficiency, the stringency of selection is increased and
reciprocally the expression levels of the polypeptide of interest
go up, so that fine-tuning is possible: for instance using a TTG
startcodon for the selection marker polypeptide, only very few
ribosomes will translate from this startcodon, resulting in very
low levels of selectable marker protein, and hence a high
stringency of selection, and at the same time almost all ribosomes
will translate the polypeptide of interest.
[0105] It is demonstrated herein that this can be used in a very
robust selection system, leading to a very large percentage of
clones that express the polypeptide of interest at high levels, as
desired. In addition, the expression levels obtained for the
polypeptide of interest appear to be significantly higher than
those obtained when an even larger number of colonies are screened
using selection systems hitherto known.
[0106] In addition to a decreased translation initiation
efficiency, it could be beneficial to also provide for decreased
translation elongation efficiency of the selectable marker
polypeptide, e.g. by mutating the coding sequence thereof so that
it comprises several non-preferred codons of the host cell, in
order to further decrease the translation levels of the marker
polypeptide and allow still more stringent selection conditions, if
desired. In certain embodiments, besides the mutation(s) that
decrease the translation efficiency according to the invention, the
selectable marker polypeptide further comprises a mutation that
reduces the activity of the selectable marker polypeptide compared
to its wild-type counterpart. This may be used to increase the
stringency of selection even further. As non-limiting examples,
proline at position 9 in the zeocin resistance polypeptide may be
mutated, e.g. to Thr or Phe, and for the neomycin resistance
polypeptide, amino acid residue 182 or 261 or both may further be
mutated (see e.g. WO 01/32901).
[0107] In some embodiments of the invention, a so-called spacer
sequence is placed downstream of the sequence encoding the
startcodon of the selectable marker polypeptide, which spacer
sequence preferably is a sequence in frame with the startcodon and
encoding a few amino acids, and that does not contain a secondary
structure (Kozak, 1990), and does not contain the sequence ATG.
Such a spacer sequence can be used to further decrease the
translation initiation frequency if a secondary structure is
present in the RNA (Kozak, 1990) of the selectable marker
polypeptide (e.g. for zeocin, possibly for blasticidin), and hence
increase the stringency of the selection system according to the
invention.
[0108] The invention also provides a DNA molecule comprising the
sequence encoding a selectable marker protein according to the
invention, which DNA molecule has been provided with a mutation
that decreases the translation efficiency of the functional
selectable marker polypeptide in a eukarytic host cell. In
preferred embodiments hereof, said DNA molecule in the coding
strand: i) has been mutated compared to the wild-type sequence
encoding said selectable marker polypeptide, such that the sequence
ATG is absent from the coding region following the startcodon of
the functional selectable marker protein up till the stopcodon of
said functional selectable marker protein open reading frame; and
ii) has a non-optimal translation start sequence of the functional
selectable marker polypeptide. Features i) and ii) can again be
provided according to the description above. Such DNA molecules
encompass a useful intermediate product according to the invention.
These molecules can be prepared first, introduced into eukaryotic
host cells and tested for functionality (for some markers this is
even possible in prokaryotic host cells), if desired in a (semi-)
quantitative manner, of the selectable marker polypeptide. They may
then be further used to prepare a DNA molecule according to the
invention, comprising the multicistronic transcription unit.
[0109] It is a preferred aspect of the invention to provide an
expression cassette comprising the DNA molecule according to the
invention, having the multicistronic transcription unit. Such an
expression cassette is useful to express sequences of interest, for
instance in host cells. An `expression cassette` as used herein is
a nucleic acid sequence comprising at least a promoter functionally
linked to a sequence of which expression is desired. Preferably, an
expression cassette further contains transcription termination and
polyadenylation sequences. Other regulatory sequences such as
enhancers may also be included. Hence, the invention provides an
expression cassette comprising in the following order:
5'-promoter--multicistronic transcription unit according to the
invention, coding for a selectable marker polypeptide and
downstream thereof a polypeptide of interest--transcription
termination sequence-3'. The promoter must be capable of
functioning in a eukaryotic host cell, i.e. it must be capable of
driving transcription of the multicistronic transcription unit. The
expression cassette may optionally further contain other elements
known in the art, e.g. splice sites to comprise introns, and the
like. In some embodiments, an intron is present behind the promoter
and before the sequence encoding the selectable marker
polypeptide.
[0110] To obtain expression of nucleic acid sequences encoding
protein, it is well known to those skilled in the art that
sequences capable of driving such expression, can be functionally
linked to the nucleic acid sequences encoding the protein,
resulting in recombinant nucleic acid molecules encoding a protein
in expressible format. In the present invention, the expression
cassette comprises a multicistronic transcription unit. In general,
the promoter sequence is placed upstream of the sequences that
should be expressed. Much used expression vectors are available in
the art, e.g. the pcDNA and pEF vector series of Invitrogen, pMSCV
and pTK-Hyg from BD Sciences, pCMV-Script from Stratagene, etc,
which can be used to obtain suitable promoters and/or transcription
terminator sequences, polyA sequences, and the like.
[0111] Where the sequence encoding the polypeptide of interest is
properly inserted with reference to sequences governing the
transcription and translation of the encoded polypeptide, the
resulting expression cassette is useful to produce the polypeptide
of interest, referred to as expression. Sequences driving
expression may include promoters, enhancers and the like, and
combinations thereof. These should be capable of functioning in the
host cell, thereby driving expression of the nucleic acid sequences
that are functionally linked to them. The person skilled in the art
is aware that various promoters can be used to obtain expression of
a gene in host cells. Promoters can be constitutive or regulated,
and can be obtained from various sources, including viruses,
prokaryotic, or eukaryotic sources, or artificially designed.
Expression of nucleic acids of interest may be from the natural
promoter or derivative thereof or from an entirely heterologous
promoter (Kaufman, 2000). Some well-known and much used promoters
for expression in eukaryotic cells comprise promoters derived from
viruses, such as adenovirus, e.g. the E1A promoter, promoters
derived from cytomegalovirus (CMV), such as the CMV immediate early
(IE) promoter (referred to herein as the CMV promoter) (obtainable
for instance from pcDNA, Invitrogen), promoters derived from Simian
Virus 40 (SV40) (Das et al, 1985), and the like. Suitable promoters
can also be derived from eukaryotic cells, such as methallothionein
(MT) promoters, elongation factor 1.alpha. (EF-1.alpha.) promoter
(Gill et al., 2001), ubiquitin C or UB6 promoter (Gill et al.,
2001; Schorpp et al, 1996), actin promoter, an immunoglobulin
promoter, heat shock promoters, and the like. Some preferred
promoters for obtaining expression in eukaryotic cells, which are
suitable promoters in the present invention, are the CMV-promoter,
a mammalian EF1-alpha promoter, a mammalian ubiquitin promoter such
as a ubiquitin C promoter, or a SV40 promoter (e.g. obtainable from
pIRES, cat.no. 631605, BD Sciences). Testing for promoter function
and strength of a promoter is a matter of routine for a person
skilled in the art, and in general may for instance encompass
cloning a test gene such as lacZ, luciferase, GFP, etc. behind the
promoter sequence, and test for expression of the test gene. Of
course, promoters may be altered by deletion, addition, mutation of
sequences therein, and tested for functionality, to find new,
attenuated, or improved promoter sequences. According to the
present invention, strong promoters that give high transcription
levels in the eukaryotic cells of choice are preferred.
[0112] In certain embodiments, a DNA molecule according to the
invention is part of a vector, e.g. a plasmid. Such vectors can
easily be manipulated by methods well known to the person skilled
in the art, and can for instance be designed for being capable of
replication in prokaryotic and/or eukaryotic cells. In addition,
many vectors can directly or in the form of isolated desired
fragment therefrom be used for transformation of eukaryotic cells
and will integrate in whole or in part into the genome of such
cells, resulting in stable host cells comprising the desired
nucleic acid in their genome.
[0113] Conventional expression systems are DNA molecules in the
form of a recombinant plasmid or a recombinant viral genome. The
plasmid or the viral genome is introduced into (eukaryotic host)
cells and preferably integrated into their genomes by methods known
in the art. In preferred embodiments, the present invention also
uses these types of DNA molecules to deliver its improved transgene
expression system. A preferred embodiment of the invention is the
use of plasmid DNA for delivery of the expression system. A plasmid
contains a number of components: conventional components, known in
the art, are an origin of replication and a selectable marker for
propagation of the plasmid in bacterial cells; a selectable marker
that functions in eukaryotic cells to identify and isolate host
cells that carry an integrated transgene expression system; the
protein of interest, whose high-level transcription is brought
about by a promoter that is functional in eukaryotic cells (e.g.
the human cytomegalovirus major immediate early promoter/enhancer,
pCMV (Boshart et al., 1985); and viral transcriptional terminators
(e.g. the SV40 polyadenylation site (Kaufman & Sharp, 1982) for
the transgene of interest and the selectable marker.
[0114] The vector used can be any vector that is suitable for
cloning DNA and that can be used for transcription of a nucleic
acid of interest. When host cells are used it is preferred that the
vector is an integrating vector. Alternatively, the vector may be
an episomally replicating vector.
[0115] It is widely appreciated that chromatin structure and other
epigenetic control mechanisms may influence the expression of
transgenes in eukaryotic cells (e.g. Whitelaw et al, 2001). The
multicistronic expression units according to the invention form
part of a selection system with a rather rigourous selection
regime. This generally requires high transcription levels in the
host cells of choice. To increase the chance of finding clones of
host cells that survive the rigorous selection regime, and possibly
to increase the stability of expression in obtained clones, it will
generally be preferable to increase the predictability of
transcription. Therefore, in preferred embodiments, an expression
cassette according to the invention further comprises at least one
chromatin control element. A `chromatin control element` as used
herein is a collective term for DNA sequences that may somehow have
an effect on the chromatin structure and therewith on the
expression level and/or stability of expression of transgenes in
their vicinity (they function `in cis`, and hence are placed
preferably within 5 kb, more preferably within 2 kb, still more
preferably within 1 kb from the transgene) within eukaryotic cells.
Such elements have sometimes been used to increase the number of
clones having desired levels of transgene expression. The
mechanisms by which these elements work may differ for and even
within different classes of such elements, and are not completely
known for all types of such elements. However, such elements have
been described, and for the purpose of the present invention
chromatin control elements are chosen from the group consisting of
matrix or scaffold attachment regions (MARs/SARs) (e.g. Phi-Van et
al, 1990; WO 02/074969, WO 2005/040377), insulators (West et al,
2002) such as the beta-globin insulator element (5' HS4 of the
chicken beta-globin locus), scs, scs', and the like (e.g. Chung et
al, 1993, 1997; Kellum and Schedl, 1991; WO 94/23046, WO 96/04390,
WO 01/02553, WO 2004/027072), a ubiquitous chromatin opening
element (UCOE) (WO 00/05393, WO 02/24930, WO 02/099089, WO
02/099070), and anti-repressor sequences(also referred to as `STAR`
sequences) (Kwaks et al, 2003; WO 03/004704). Non-limiting examples
of MAR/SAR sequences that could be used in the current invention
are the chicken lysosyme 5' MAR (Phi-Van et al, 1990) or fragments
thereof, e.g. the B, K and F regions as described in WO 02/074969);
DNA sequences comprising at least one bent DNA element and at least
one binding site for a DNA binding protein, preferably containing
at least 10% of dinucleotide TA, and/or at least 12% of
dinucleotide AT on a stretch of 100 contiguous base pairs, such as
a sequence selected from the group of comprising the sequences SEQ
ID Nos 1 to 27 in WO 2005/040377, fragments of any one of SEQ ID
Nos 1 to 27 in WO 2005/040377 being at least 100 nucleotides in
length and having MAR activity, sequences that are at least 70%
identical in nucleotide sequence to any one of SEQ ID Nos 1 to 27
in WO 2005/040377 or fragments thereof and having MAR activity,
wherein MAR activity is defined as being capable of binding to
nuclear matrices/scaffolds in vitro and/or of altering the
expression of coding sequences operably linked to a promoter;
sequences chosen from any one of SEQ ID NO: 1 to 5 in WO 02/074969,
fragments of any one of any one of SEQ ID NO: 1 to 5 in WO
02/074969 and having MAR activity, sequences that are at least 70%
identical in nucleotide sequence to any one of SEQ ID NO: 1 to 5 in
WO 02/074969 or fragments thereof and having MAR activity;
sequences chosen from SEQ ID NO: 1 and SEQ ID NO: 2 in WO
2004/027072, functional fragments thereof and sequences being at
least 70% identical thereto. A non-limiting example of insulator
sequences that could be used in the present invention is a sequence
that comprises SEQ ID NO:1 of WO 01/02553. Non-limiting examples of
UCOEs that could be used in the present invention are sequences
depicted in FIGS. 2 and 7 of WO 02/24930, functional fragments
thereof and sequences being at least 70% identical thereto while
still retaining activity; sequences comprising SEQ ID NO: 28 of US
2005/181428, functional fragments thereof and sequences being at
least 70% identical thereto while still retaining activity.
[0116] Preferably, said chromatin control element is an
anti-repressor sequence, preferably chosen from the group
consisting of: a) any one SEQ. ID. NO. 1 through SEQ. ID. NO. 66;
b) fragments of any one of SEQ. ID. NO. 1 through SEQ. ID. NO. 66,
wherein said fragments have anti-repressor activity (`functional
fragments`); c) sequences that are at least 70% identical in
nucleotide sequence to a) or b) wherein said sequences have
anti-repressor activity (`functional derivatives`); and d) the
complement to any one of a) to c). Preferably, said chromatin
control element is chosen from the group consisting of STAR67 (SEQ.
ID. NO. 66), STAR7 (SEQ. ID. NO. 7), STAR9 (SEQ. ID. NO. 9), STAR17
(SEQ. ID. NO. 17), STAR27 (SEQ. ID. NO. 27), STAR29 (SEQ. ID. NO.
29), STAR43 (SEQ. ID. NO. 43), STAR44 (SEQ. ID. NO. 44), STAR45
(SEQ. ID. NO. 45), STAR47 (SEQ. ID. NO. 47), STAR61 (SEQ. ID. NO.
61), or a functional fragment or derivative of said STAR sequences.
In a particularly preferred embodiment, said STAR sequence is STAR
67 (SEQ. ID. NO. 66) or a functional fragment or derivative
thereof. In certain preferred embodiments, STAR 67 or a functional
fragment or derivative thereof is positioned upstream of a promoter
driving expression of the multicistronic transcription unit. In
other preferred embodiments, the expression cassettes according to
the invention are flanked on both sides by at least one
anti-repressor sequence.
[0117] Sequences having anti-repressor activity as used herein are
sequences that are capable of at least in part counteracting the
repressive effect of HP1 or HPC2 proteins when these proteins are
tethered to DNA. Sequences having anti-repressor activity
(sometimes also referred to as anti-repressor sequences or
anti-repressor elements herein) suitable for the present invention,
have been disclosed in WO 03/004704, incorporated herein by
reference, and were coined "STAR" sequences therein (wherever a
sequence is referred to as a STAR sequence herein, this sequence
has anti-repressor activity according to the invention). As a
non-limiting example, the sequences of 66 anti-repressor elements,
named STAR1-65 (see WO 03/004704) and STAR67, are presented herein
as SEQ. ID. NOs. 1-65 and 66, respectively.
[0118] According to the invention, a functional fragment or
derivative of a given anti-repressor element is considered
equivalent to said anti-repressor element, when it still has
anti-repressor activity. The presence of such anti-repressor
activity can easily be checked by the person skilled in the art,
for instance by the assay described below. Functional fragments or
derivatives can easily be obtained by a person skilled in the art
of molecular biology, by starting with a given anti-repressor
sequence, and making deletions, additions, substitutions,
inversions and the like (see e.g. WO 03/004704). A functional
fragment or derivative also comprises orthologs from other species,
which can be found using the known anti-repressor sequences by
methods known by the person skilled in the art (see e.g. WO
03/004704). Hence, the present invention encompasses fragments of
the anti-repressor sequences, wherein said fragments still have
anti-repressor activity. The invention also encompasses sequences
that are at least 70% identical in nucleotide sequence to said
sequences having anti-repressor activity or to functional fragments
thereof having anti-repressor activity, as long as these sequences
that are at least 70% identical still have the anti-repressor
activity according to the invention. Preferably, said sequences are
at least 80% identical, more preferably at least 90% identical and
still more preferably at least 95% identical to the reference
native sequence or functional fragment thereof. For fragments of a
given sequence, percent identity refers to that portion of the
reference native sequence that is found in the fragment.
[0119] Sequences having anti-repressor activity according to the
invention can be obtained by various methods, including but not
limited to the cloning from the human genome or from the genome of
another organism, or by for instance amplifying known
anti-repressor sequences directly from such a genome by using the
knowledge of the sequences, e.g. by PCR, or can in part or wholly
be chemically synthesized.
[0120] Sequences having anti-repressor activity, and functional
fragments or derivatives thereof, are structurally defined herein
by their sequence and in addition are functionally defined as
sequences having anti-repressor activity, which can be determined
with the assay described below.
[0121] Any sequence having anti-repressor activity according to the
present invention should at least be capable of surviving the
following functional assay (see WO 03/004704, example 1,
incorporated herein by reference).
[0122] Human U-2 OS cells (ATCC HTB-96) are stably transfected with
the pTet-Off plasmid (Clontech K1620-A) and with nucleic acid
encoding a LexA-repressor fusion protein containing the LexA DNA
binding domain and the coding region of either HP1 or HPC2
(Drosophila Polycomb group proteins that repress gene expression
when tethered to DNA; the assay works with either fusion protein)
under control of the Tet-Off transcriptional regulatory system
(Gossen and Bujard, 1992). These cells are referred to below as the
reporter cells for the anti-repressor activity assay. A reporter
plasmid, which provides hygromycin resistance, contains a
polylinker sequence positioned between four LexA operator sites and
the SV40 promoter that controls the zeocin resistance gene. The
sequence to be tested for anti-repressor activity can be cloned in
said polylinker. Construction of a suitable reporter plasmid, such
as pSelect, is described in example 1 and FIG. 1 of WO 00/004704.
The reporter plasmid is transfected into the reporter cells, and
the cells are cultured under hygromycin selection (25 .mu.g/ml;
selection for presence of the reporter plasmid) and tetracycline
repression (doxycycline, 10 .mu.g/ml; prevents expression of the
LexA-repressor fusion protein). After 1 week of growth under these
conditions, the doxycycline concentration is reduced to 0.1 ng/ml
to induce the LexA-repressor gene, and after 2 days zeocin is added
to 250 .mu.g/ml. The cells are cultured for 5 weeks, until the
control cultures (transfected with empty reporter plasmid, i.e.
lacking a cloned anti-repressor sequence in the polylinker) are
killed by the zeocin (in this control plasmid, the SV40 promoter is
repressed by the LexA-repressor fusion protein that is tethered to
the LexA operating sites, resulting in insufficient zeocin
expression in such cells to survive zeocin selection). A sequence
has anti-repressor activity according to the present invention if,
when said sequence is cloned in the polylinker of the reporter
plasmid, the reporter cells survive the 5 weeks selection under
zeocin. Cells from such colonies can still be propagated onto new
medium containing zeocin after the 5 weeks zeocin selection,
whereas cells transfected with reporter plasmids lacking
anti-repressor sequences cannot be propagated onto new medium
containing zeocin. Any sequence not capable of conferring such
growth after 5 weeks on zeocin in this assay, does not qualify as a
sequence having anti-repressor activity, or functional fragment or
functional derivative thereof according to the present invention.
As an example, other known chromatin control elements such as those
tested by Van der Vlag et al (2000), including Drosophila scs
(Kellum and Schedl, 1991), 5'-HS4 of the chicken .beta.-globin
locus (Chung et al, 1993, 1997) or Matrix Attachment Regions (MARs)
(Phi-Van et al., 1990), do not survive this assay.
[0123] In addition, it is preferred that the anti-repressor
sequence or functional fragment or derivative thereof confers a
higher proportion of reporter over-expressing clones when flanking
a reporter gene (e.g. luciferase, GFP) which is integrated into the
genome of U-2 OS or CHO cells, compared to when said reporter gene
is not flanked by anti-repressor sequences, or flanked by weaker
repression blocking sequences such as Drosophila scs. This can be
verified using for instance the pSDH vector, or similar vectors, as
described in example 1 and FIG. 2 of WO 03/004704.
[0124] Anti-repressor elements can have at least one of three
consequences for production of protein: (1) they increase the
predictability of identifying host cell lines that express a
protein at industrially acceptable levels (they impair the ability
of adjacent heterochromatin to silence the transgene, so that the
position of integration has a less pronounced effect on
expression); (2) they result in host cell lines with increased
protein yields; and/or (3) they result in host cell lines that
exhibit more stable protein production during prolonged
cultivation.
[0125] Any STAR sequence can be used in the expression cassettes
according to the present invention, but the following STAR
sequences are particularly useful: STAR67 (SEQ. ID. NO. 66), STAR7
(SEQ. ID. NO. 7), STAR9 (SEQ. ID. NO. 9), STAR17 (SEQ. ID. NO. 17),
STAR27 (SEQ. ID. NO. 27), STAR29 (SEQ. ID. NO. 29), STAR43 (SEQ.
ID. NO. 43), STAR44 (SEQ. ID. NO. 44), STAR45 (SEQ. ID. NO. 45),
STAR47 (SEQ. ID. NO. 47), STAR61 (SEQ. ID. NO. 61), or functional
fragments or derivatives of these STAR sequences.
[0126] In certain embodiments said anti-repressor sequence,
preferably STAR67, is placed upstream of said promoter, preferably
such that less than 2 kb are present between the 3' end of the
anti-repressor sequence and the start of the promoter sequence. In
preferred embodiments, less than 1 kb, more preferably less than
500 nucleotides (nt), still more preferably less than about 200,
100, 50, or 30 nt are present between the 3' end of the
anti-repressor sequence and the start of the promoter sequence. In
certain preferred embodiments, the anti-repressor sequence is
cloned directly upstream of the promoter, resulting in only about
0-20 nt between the 3' end of the anti-repressor sequence and the
start of the promoter sequence.
[0127] For the production of multimeric proteins, two or more
expression cassettes can be used. Preferably, both expression
cassettes are multicistronic expression cassettes according to the
invention, each coding for a different selectable marker protein,
so that selection for both expression cassettes is possible. This
embodiment has proven to give good results, e.g. for the expression
of the heavy and light chain of antibodies. It will be clear that
both expression cassettes may be placed on one nucleic acid
molecule or both may be present on a separate nucleic acid
molecule, before they are introduced into host cells. An advantage
of placing them on one nucleic acid molecule is that the two
expression cassettes are present in a single predetermined ratio
(e.g. 1:1) when introduced into host cells. On the other hand, when
present on two different nucleic acid molecules, this allows the
possibility to vary the molar ratio of the two expression cassettes
when introducing them into host cells, which may be an advantage if
the preferred molar ratio is different from 1:1 or when it is
unknown beforehand what is the preferred molar ratio, so that
variation thereof and empirically finding the optimum can easily be
performed by the skilled person. According to the invention,
preferably at least one of the expression cassettes, but more
preferably each of them, comprises a chromatin control element,
more preferably an anti-repressor sequence.
[0128] In another embodiment, the different subunits or parts of a
multimeric protein are present on a single expression cassette.
[0129] Instead of or in addition to the presence of a STAR sequence
placed upstream of a promoter in an expression cassette, it has
proven highly beneficial to provide a STAR sequence on both sides
of an expression cassette, such that expression cassette comprising
the transgene is flanked by two STAR sequences, which in certain
embodiments are essentially identical to each other.
[0130] It is shown herein that the combination of a first
anti-repressor element upstream of a promoter and flanking the
expression cassette by two other anti-repressor sequences provides
superior results.
[0131] As at least some anti-repressor sequences can be directional
(WO 00/004704), the anti-repressor sequences flanking the
expression cassette (anti-repressor A and B) may beneficially
placed in opposite direction with respect to each other, such that
the 3' end of each of these anti-repressor sequences is facing
inwards to the expression cassette (and to each other). Hence, in
preferred embodiments, the 5' side of an anti-repressor element
faces the DNA/chromatin of which the influence on the transgene is
to be diminished by said anti-repressor element. For an
anti-repressor sequence upstream of a promoter in an expression
cassette, the 3' end faces the promoter. The sequences of the
anti-repressor elements in the sequence listing (SEQ. ID. NOs.
1-66) are given in 5' to 3' direction, unless otherwise
indicated.
[0132] In certain embodiments, transcription units or expression
cassettes according to the invention are provided, further
comprising: a) a transcription pause (TRAP) sequence upstream of
the promoter that drives transcription of the multicistronic
transcription unit, said TRAP being in a 5' to 3' direction; or b)
a TRAP sequence downstream of said open reading frame of the
polypeptide of interest and preferably downstream of the
transcription termination sequence of said multicistronic
transcription unit, said TRAP being in a 3' to 5' orientation; or
c) both a) and b); wherein a TRAP sequence is functionally defined
as a sequence which when placed into a transcription unit, results
in a reduced level of transcription in the nucleic acid present on
the 3' side of the TRAP when compared to the level of transcription
observed in the nucleic acid on the 5' side of the TRAP.
Non-limiting examples of TRAP sequences are transcription
termination and/or polyadenylation signals. One non-limiting
example of a TRAP sequence is given in SEQ. ID. NO. 142. Examples
of other TRAP sequences, methods to find these, and uses thereof
have been described in WO 2004/055215.
[0133] DNA molecules comprising multicistronic transcription units
and/or expression cassettes according to the present invention can
be used for improving expression of nucleic acid, preferably in
host cells. The terms "cell"/"host cell" and "cell line"/"host cell
line" are respectively typically defined as a cell and homogeneous
populations thereof that can be maintained in cell culture by
methods known in the art, and that have the ability to express
heterologous or homologous proteins.
[0134] Prokaryotic host cells can be used to propagate and/or
perform genetic engineering with the DNA molecules of the
invention, especially when present on plasmids capable of
replicating in prokaryotic host cells such as bacteria.
[0135] A host cell according to the present invention preferably is
a eukaryotic cell, more preferably a mammalian cell, such as a
rodent cell or a human cell or fusion between different cells. In
certain non-limiting embodiments, said host cell is a U-2 OS
osteosarcoma, CHO (Chinese hamster ovary), HEK 293, HuNS-1 myeloma,
WERI-Rb-1 retinoblastoma, BHK, Vero, non-secreting mouse myeloma
Sp2/0-Ag 14, non-secreting mouse myeloma NS1, NCI-H295R adrenal
gland carcinomal or a PER.C6.RTM. cell.
[0136] In certain embodiments of the invention, a host cell is a
cell expressing at least E1A, and preferably also E1B, of an
adenovirus. As non-limiting examples, such a cell can be derived
from for instance human cells, for instance from a kidney (example:
HEK 293 cells, see Graham et al, 1977), lung (e.g. A549, see e.g.
WO 98/39411) or retina (example: HER cells marketed under the trade
mark PER.C6.RTM., see U.S. Pat. No. 5,994,128), or from amniocytes
(e.g. N52.E6, described in U.S. Pat. No. 6,558,948), and similarly
from other cells. Methods for obtaining such cells are described
for instance in U.S. Pat. No. 5,994,128 and U.S. Pat. No.
6,558,948. PER.C6 cells for the purpose of the present invention
means cells from an upstream or downstream passage or a descendent
of an upstream or downstream passage of cells as deposited under
ECACC no. 96022940, i.e. having the characteristics of those cells.
It has been previously shown that such cells are capable of
expression of proteins at high levels (e.g. WO 00/63403, and Jones
et al, 2003). In other preferred embodiments, the host cells are
CHO cells, for instance CHO-K1, CHO-S, CHO-DG44, CHO-DUKXB11, and
the like. In certain embodiments, said CHO cells have a
dhfr.sup.-phenotype.
[0137] Such eukaryotic host cells can express desired polypeptides,
and are often used for that purpose. They can be obtained by
introduction of a DNA molecule of the invention, preferably in the
form of an expression cassette, into the cells. Preferably, the
expression cassette is integrated in the genome of the host cells,
which can be in different positions in various host cells, and
selection will provide for a clone where the transgene is
integrated in a suitable position, leading to a host cell clone
with desired properties in terms of expression levels, stability,
growth characteristics, and the like. Alternatively the
multicistronic transcription unit may be targeted or randomly
selected for integration into a chromosomal region that is
transcriptionally active, e.g. behind a promoter present in the
genome. Selection for cells containing the DNA of the invention can
be performed by selecting for the selectable marker polypeptide,
using routine methods known by the person skilled in the art. When
such a multicistronic transcription unit is integrated behind a
promoter in the genome, an expression cassette according to the
invention can be generated in situ, i.e. within the genome of the
host cells.
[0138] Preferably the host cells are from a stable clone that can
be selected and propagated according to standard procedures known
to the person skilled in the art. A culture of such a clone is
capable of producing polypeptide of interest, if the cells comprise
the multicistronic transcription unit of the invention. Cells
according to the invention preferably are able to grow in
suspension culture in serum-free medium.
[0139] In preferred embodiments, the DNA molecule comprising the
multicistronic transcription unit of the invention, preferably in
the form of an expression cassette, is integrated into the genome
of the eukaryotic host cell according to the invention. This will
provide for stable inheritance of the multicistronic transcription
unit.
[0140] Selection for the presence of the selectable marker
polypeptide, and hence for expression, can be performed during the
initial obtaining of the cells, and could be lowered or stopped
altogether after stable clones have been obtained. It is however
also possible to apply the selection agent during later stages
continuously, or only occasionally, possibly at lower levels than
during initial selection of the host cells.
[0141] A polypeptide of interest according to the invention can be
any protein, and may be a monomeric protein or a (part of a)
multimeric protein. A multimeric protein comprises at least two
polypeptide chains. Non-limiting examples of a protein of interest
according to the invention are enzymes, hormones, immunoglobulin
chains, therapeutic proteins like anti-cancer proteins, blood
coagulation proteins such as Factor VIII, multi-functional
proteins, such as erythropoietin, diagnostic proteins, or proteins
or fragments thereof useful for vaccination purposes, all known to
the person skilled in the art.
[0142] In certain embodiments, an expression cassette of the
invention encodes an immunoglobulin heavy or light chain or an
antigen binding part, derivative and/or analogue thereof. In a
preferred embodiment a protein expression unit according to the
invention is provided, wherein said protein of interest is an
immunoglobulin heavy chain. In yet another preferred embodiment a
protein expression unit according to the invention is provided,
wherein said protein of interest is an immunoglobulin light chain.
When these two protein expression units are present within the same
(host) cell a multimeric protein and more specifically an
immunoglobulin, is assembled. Hence, in certain embodiments, the
protein of interest is an immunoglobulin, such as an antibody,
which is a multimeric protein. Preferably, such an antibody is a
human or humanized antibody. In certain embodiments thereof, it is
an IgG, IgA, or IgM antibody. An immunoglobulin may be encoded by
the heavy and light chains on different expression cassettes, or on
a single expression cassette. Preferably, the heavy and light chain
are each present on a separate expression cassette, each having its
own promoter (which may be the same or different for the two
expression cassettes), each comprising a multicistronic
transcription unit according to the invention, the heavy and light
chain being the polypeptide of interest, and preferably each coding
for a different selectable marker protein, so that selection for
both heavy and light chain expression cassette can be performed
when the expression cassettes are introduced and/or present in a
eukaryotic host cell.
[0143] The polypeptide of interest may be from any source, and in
certain embodiments is a mammalian protein, an artificial protein
(e.g. a fusion protein or mutated protein), and preferably is a
human protein.
[0144] Obviously, the configurations of the expression cassettes of
the present invention may also be used when the ultimate goal is
not the production of a polypeptide of interest, but the RNA
itself, for instance for producing increased quantities of RNA from
an expression cassette, which may be used for purposes of
regulating other genes (e.g. RNAi, antisense RNA), gene therapy, in
vitro protein production, etc.
[0145] In one aspect, the invention provides a method for
generating a host cell expressing a polypeptide of interest, the
method comprising the steps of: a) introducing into a plurality of
precursor cells an expression cassette according to the invention,
and b) culturing the generated cells under conditions selecting for
expression of the selectable marker polypeptide, and c) selecting
at least one host cell producing the polypeptide of interest. This
novel method provides a very good result in terms of the ratio of
obtained clones versus clones with high expression of the desired
polypeptide. Using the most stringent conditions, i.e. the weakest
translation efficiency for the selectable marker polypeptide (using
the weakest translation start sequence), far fewer colonies are
obtained using the same concentration of selection agent than with
known selection systems, and a relatively high percentage of the
obtained clones produces the polypeptide of interest at high
levels. In addition, the obtained levels of expression appear
higher than those obtained when an even larger number of clones
using the known selection systems are used.
[0146] It is an additional advantage that the selection system is
swift because it does not require copy number amplification of the
transgene. Hence, cells with low copy numbers of the multicistronic
transcription units already provide high expression levels. High
transgene copy numbers of the transgene may be prone to genetic
instability and repeat-induced silencing (e.g. Kim et al, 1998;
McBurney et al, 2002). Therefore, an additional advantage of the
embodiments of the invention with relatively low transgene copy
numbers is that lower copy numbers are anticipated to be less prone
to recombination and to repeat-induced silencing, and therefore
less problems in this respect are anticipated when using host cells
with a limited number of copies of the transgene compared to host
cells obtained using an amplification system where hundreds or even
thousands of copies of the selectable marker and protein of
interest coding sequences may be present in the genome of the cell.
The present invention provides examples of high expression levels,
using the multicistronic transcription unit selection system, while
the copy number of the transgene is relatively low, i.e less than
30 copies per cell, or even less than 20 copies per cell. Hence,
the present invention allows the generation of host cells according
to the invention, comprising less than 30 copies of the
multicistronic transcription unit in the genome of the host cells,
preferably less than 25, more preferably less than 20 copies, while
at the same time providing sufficient expression levels of the
polypeptide of interest for commercial purposes, e.g. more than 15,
preferably more than 20 pg/cell/day of an antibody.
[0147] While clones having relatively low copy numbers of the
multicistronic transcription units and high expression levels can
be obtained, the selection system of the invention nevertheless can
be combined with amplification methods to even further improve
expression levels. This can for instance be accomplished by
amplification of a co-integrated dhfr gene using methotrexate, for
instance by placing dhfr on the same nucleic acid molecule as the
multicistronic transcription unit of the invention, or by
cotransfection when dhfr is on a separate DNA molecule.
[0148] In one aspect, the invention provides a method for producing
a polypeptide of interest, the method comprising culturing a host
cell, said host cell comprising a DNA molecule comprising a
multicistronic expression unit or an expression cassette according
to the invention, and expressing the polypeptide of interest from
the coding sequence for the polypeptide of interest.
[0149] The host cell for this aspect is a eukaryotic host cell,
preferably a mammalian cell, such as a CHO cell, further as
described above.
[0150] Introduction of nucleic acid that is to be expressed in a
cell, can be done by one of several methods, which as such are
known to the person skilled in the art, also dependent on the
format of the nucleic acid to be introduced. Said methods include
but are not limited to transfection, infection, injection,
transformation, and the like. Suitable host cells that express the
polypeptide of interest can be obtained by selection as described
above.
[0151] In certain embodiments, selection agent is present in the
culture medium at least part of the time during the culturing,
either in sufficient concentrations to select for cells expressing
the selectable marker polypeptide or in lower concentrations. In
preferred embodiments, selection agent is no longer present in the
culture medium during the production phase when the polypeptide is
expressed.
[0152] Culturing a cell is done to enable it to metabolize, and/or
grow and/or divide and/or produce recombinant proteins of interest.
This can be accomplished by methods well known to persons skilled
in the art, and includes but is not limited to providing nutrients
for the cell. The methods comprise growth adhering to surfaces,
growth in suspension, or combinations thereof. Culturing can be
done for instance in dishes, roller bottles or in bioreactors,
using batch, fed-batch, continuous systems such as perfusion
systems, and the like. In order to achieve large scale (continuous)
production of recombinant proteins through cell culture it is
preferred in the art to have cells capable of growing in
suspension, and it is preferred to have cells capable of being
cultured in the absence of animal- or human-derived serum or
animal- or human-derived serum components.
[0153] The conditions for growing or multiplying cells (see e.g.
Tissue Culture, Academic Press, Kruse and Paterson, editors (1973))
and the conditions for expression of the recombinant product are
known to the person skilled in the art. In general, principles,
protocols, and practical techniques for maximizing the productivity
of mammalian cell cultures can be found in Mammalian Cell
Biotechnology: a Practical Approach (M. Butler, ed., IRL Press,
1991).
[0154] In a preferred embodiment, the expressed protein is
collected (isolated), either from the cells or from the culture
medium or from both. It may then be further purified using known
methods, e.g. filtration, column chromatography, etc, by methods
generally known to the person skilled in the art.
[0155] The selection method according to the present invention
works in the absence of chromatin control elements, but improved
results are obtained when the multicistronic expression units are
provided with such elements. The selection method according to the
present invention works particularly well when an expression
cassette according to the invention, comprising at least one
anti-repressor sequence is used. Depending on the selection agent
and conditions, the selection can in certain cases be made so
stringent, that only very few or even no host cells survive the
selection, unless anti-repressor sequences are present. Hence, the
combination of the novel selection method and anti-repressor
sequences provides a very attractive method to obtain only limited
numbers of colonies with a greatly improved chance of high
expression of the polypeptide of interest therein, while at the
same time the obtained clones comprising the expression cassettes
with anti-repressor sequences provide for stable expression of the
polypeptide of interest, i.e. they are less prone to silencing or
other mechanisms of lowering expression than conventional
expression cassettes.
[0156] In certain embodiments, almost no clones are obtained when
no anti-repressor sequence is present in the expression cassette
according to the invention, providing for very stringent selection.
The novel selection system disclosed herein therefore also provides
the possibility to test parts of anti-repressor elements for
functionality, by analyzing the effects of such sequences when
present in expression cassettes of the invention under selection
conditions. This easy screen, which provides an almost or even
complete black and white difference in many cases, therefore can
contribute to identifying functional parts or derivatives from
anti-repressor sequences. When known anti-repressor sequences are
tested, this assay can be used to characterize them further. When
fragments of known anti-repressor sequences are tested, the assay
will provide functional fragments of such known anti-repressor
sequences.
[0157] The practice of this invention will employ, unless otherwise
indicated, conventional techniques of immunology, molecular
biology, microbiology, cell biology, and recombinant DNA, which are
within the skill of the art. See e.g. Sambrook, Fritsch and
Maniatis, Molecular Cloning: A Laboratory Manual, 2.sup.nd edition,
1989; Current Protocols in Molecular Biology, Ausubel F M, et al,
eds, 1987; the series Methods in Enzymology (Academic Press, Inc.);
PCR2: A Practical Approach, MacPherson M J, Hams B D, Taylor G R,
eds, 1995; Antibodies: A Laboratory Manual, Harlow and Lane, eds,
1988.
[0158] The invention is further explained in the following
examples. The examples do not limit the invention in any way. They
merely serve to clarify the invention.
EXAMPLES
[0159] Examples 1-7 describe the testing of STAR67 and other STAR
sequences in various configurations and under various
circumstances. Examples 8 and further describe the novel selection
system of the invention.
Example 1
Construction of STAR67 Vectors
[0160] A novel anti-repressor (STAR) sequence was isolated using a
genetic screen as described in WO 03/004704, and this novel
sequence was coined STAR67. The effects of STAR67 on expression of
transgenes in mammalian cell lines were tested. Here we describe
the construction of the various constructs.
Materials and Methods
[0161] Three plasmids were created (FIG. 1):
[0162] A) CMV-d2EGFP-ires-Zeo (CMV Control),
[0163] B) STAR67-CMV-d2EGFP-ires-Zeo (CMV-STAR67),
[0164] C) STAR7-STAR67-CMV-d2EGFP-ires-Zeo-STAR7 (CMV-STAR67
7/7)
[0165] The construction of construct A is described below. Plasmid
pd2EGFP (Clontech 6010-1) was modified by insertion of a linker at
the BsiWI site to yield pd2EGFP-link. The linker, made by annealing
oligonucleotides GTACGGATATCAGATCTTTAATTAAG (SEQ. ID. NO. 67) and
GTACCTTAATTAAAGATCTGATAT (SEQ. ID. NO. 68), introduced sites for
the PacI, BglII, and EcoRV restriction endonucleases. This created
the multiple cloning site MCSII for insertion of STAR elements.
Then primers GATCAGATCTGGCGCGCCATTTAAATCGTCTCGCGCGTTTCGGTGATGACGG
(SEQ. ID. NO. 69) and (AGGCGGATCCGAATGTATTTAGAAAAATAAACAAATAGGGG
(SEQ. ID. NO. 70) were used to amplify a region of 0.37 kb from
pd2EGFP, which was inserted into the BglII site of pIRES (Clontech
6028-1) to yield pIRES-stuf. This introduced sites for the AscI and
SwaI restriction endonucleases at MCSI, and acts as a "stuffer
fragment" to avoid potential interference between STAR elements and
adjacent promoters. pIRES-stuf was digested with BglII and FspI to
liberate a DNA fragment composed of the stuffer fragment, the CMV
promoter, the IRES element (flanked by multiple cloning sites MCS A
and MCS B), and the SV40 polyadenylation signal. This fragment was
ligated with the vector backbone of pd2EGFP-link produced by
digestion with BamHI and StuI, to yield pIRES-link.
[0166] The open reading frame of the zeocin-resistance gene was
inserted into BamHI/NotI sites downstream of the pIRES as follows:
the zeocin-resistance ORF was amplified by PCR with primers
GATCGGATCCTTCGAAATGGCCAAGTTGACCAGTGC (SEQ. ID. NO. 71) and
AGGCGCGGCCGCAATTCTCAGTCCTGCTCCTC (SEQ. ID. NO. 72) from plasmid
pCMV/zeo (Invitrogen, cat.no. V50120), digested with BamHI and
NotI, and ligated with BamHI/NotI-digested pIRES-link to yield
pIRES-link-zeo. The d2EGFP reporter ORF was introduced into
pIRES-link-zeo by amplification of pd2EGFP (Clontech 6010-1) with
primers GATCGAATTCTCGCGAATGGTGAGCAAGCAGATCCTGAAG (SEQ. ID. NO. 73)
and AGGCGAATTCACCGGTGTTTAAACTTACACCCACTCGTGCAGGCTGCCCAGG (SEQ. ID.
NO. 74), and insertion of the EcoRI-digested d2EGFP cassette into
the EcoRI site in the pIRES-link-zeo plasmid. This created
construct A, CMV-d2EGFP-IRES-Zeo (CMV Control).
[0167] STAR67 was cloned upstream of the CMV promoter, in the AscI
site (about 15 nt remaining between STAR67 and the promoter). This
created construct B, STAR67-CMV-d2EGFP-ires-Zeo (CMV-STAR67).
[0168] STAR67 was also tested in the context of a cassette that
contains also the STAR7, cloned directionally in the 5' SalI and
XbaI sites and 3' BglII and PacI sites to flank the entire cassette
with STAR7. This is construct C (CMV-STAR67 7/7).
Example 2
STAR67 Enhances the Expression Level from CMV, EF1.alpha. and UB6
Promoters in Stably Transfected CHO Cells
[0169] We tested whether the presence of STAR67 adjacent to the
CMV, EF1.alpha. and UB6 promoters influences the expression level
of these promoters in CHO cells. The constructs A and B (FIG. 1)
described in Example 1 are used for this purpose, modified for the
respective promoters:
[0170] 1 CMV-d2EGFP-ires-Zeo (CMV Control)
[0171] 2 STAR67-CMV-d2EGFP-ires-Zeo (CMV-STAR67)
[0172] 3 EF1.alpha.-d2EGFP-ires-Zeo (EF1.alpha. Control)
[0173] 4 STAR67-EF1.alpha.-d2EGFP-ires-Zeo (EF1.alpha.-STAR67)
[0174] 5 UB6-d2EGFP-ires-Zeo (UB6 Control)
[0175] 6 STAR67-UB6-d2EGFP-ires-Zeo (UB6-STAR67).
Materials and Methods
[0176] The UB6 and EF1.alpha. promoters were exchanged for the CMV
promoter in the plasmids described in FIG. 1. The UB6 promoter was
cloned as follows. A DNA 0.37 kb stuffer from the pd2EGFP plasmid
was amplified by PCR, as described in example 1, using primers
identified by SEQ. ID. NOs. 69 and 70. The resulting DNA stuffer
was cloned in the BglII site of pUB6/V5-His [Invitrogen V250-20],
creating pUB6-stuf. From pUB6-stuf an AscI-SacI fragment was cloned
into CMV-d2EGFP-IRES-Zeo, from which the CMV promoter was
removed.
[0177] The EF1.alpha. promoter was amplified by PCR with
pEF1.alpha./NV5-His [Invitrogen V920-20] as template, using primers
GATCGGCGCGCCATTTAAATCCGAAAAGTGCCACCTGACG (SEQ. ID. NO. 79) and
AGGCGGGACCCCCTCACGACACCTGAAATGGAAG (SEQ. ID. NO. 80). The PCR
fragment was cloned in the AscI and PpuMI sites of
CMV-d2EGFP-IRES-Zeo, from which the CMV promoter was removed.
[0178] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) was
cultured in HAMS-F12 medium +10% Fetal Calf Serum containing 2 mM
glutamine, 100 U/ml penicillin, and 100 micrograms/ml streptomycin
at 37.degree. C./5% CO.sub.2. Cells were transfected with the
plasmids using Lipofectamine 2000 (Invitrogen) as described by the
manufacturer. Briefly, cells were seeded to culture vessels and
grown overnight to 70-90% confluence. Lipofectamine reagent was
combined with plasmid DNA at a ratio of 6 microliters per microgram
(e.g. for a 10 cm Petri dish, 20 micrograms DNA and 120 microliters
Lipofectamine) and added to the cells. After overnight incubation
the transfection mixture was replaced with fresh medium, and the
transfected cells were incubated further. After overnight
cultivation, cells were trypsinized and seeded into fresh culture
vessels with fresh medium. After another overnight incubation
zeocin was added to a concentration of 50 .mu.g/ml and the cells
were cultured further. After another three days the medium was
replaced by fresh medium containing zeocin (100 .mu.g/ml) and
cultured further. When individual colonies became visible
(approximately ten days after transfection) medium was removed and
replaced with fresh medium without zeocin. Individual clones were
isolated and transferred to 24-well plates in medium without
zeocin. One day after isolation of the colonies zeocin was added to
the medium. Expression of the d2EGFP reporter gene was assessed
approximately 3 weeks after transfection. d2EGFP expression levels
in the colonies were measured after periods of two weeks. After the
initial two weeks after transfection when the first d2EGFP
measurements were performed, the colonies were cultured in medium
without zeocin or other antibiotics. This continued for the
remainder of the experiment.
Results
[0179] FIG. 2 shows that transfection of the construct that
contains STAR67 cloned upstream of the CMV promoter resulted in a
number of CHO colonies that express significantly higher levels of
d2EGFP protein, as compared to the "empty" control without STAR67,
CMV Control. The average of the d2EGFP signal in the 10 colonies
transfected with the CMV Control plasmid was 34, when measured 25
days after transfection. 60 days after transfection the average of
the d2EGFP signal in these 10 colonies was reduced to 13,
indicating that expression is not stable over time. In comparison,
the average of the d2EGFP signal in the 10 colonies transfected
with the STAR67-CMV plasmid was 42 when measured after 25 days and
32 measured 60 days after transfection. Hence 60 days after
transfection, a STAR67-encompassing CMV construct conveyed a factor
2.5 higher CMV promoter driven expression level of the reporter
protein in stably transfected clones. Importantly, 25 days after
transfection, after the first measurement, selection pressure was
removed by culturing the colonies in medium without zeocin. Hence,
colonies containing the STAR67 construct are more stable over time
in the absence of selection pressure than colonies that do not
contain a STAR67 construct.
[0180] FIG. 3 shows that transfection of the construct that
contains STAR67 cloned upstream of the EF1.alpha.-promoter resulted
in a number of CHO colonies that express significantly higher
levels of d2EGFP protein, as compared to the "empty" control
without STAR67, EF1.alpha. Control. The average of the d2EGFP
signal in the 10 colonies transfected with the EF1.alpha. Control
plasmid was 31, when measured 25 days after transfection. 60 days
after transfection the average of the d2EGFP signal in these 10
colonies was 26. In comparison, the average of the d2EGFP signal in
the 10 colonies transfected with the EF1.alpha.-STAR67 plasmid was
60 when measured after 25 days and 76 measured 60 days after
transfection. Hence, both after 25 and 60 days after transfection,
a STAR67-encompassing EF1.alpha. construct conveyed a factor 2.9
higher EF1.alpha. promoter driven expression level of the reporter
protein in stably transfected clones.
[0181] FIG. 4 shows that transfection of the construct that
contains STAR67 cloned upstream of the UB6 promoter resulted in a
number of CHO colonies that express significantly higher levels of
d2EGFP protein, as compared to the "empty" control without STAR67,
UB6 Control. The average of the d2EGFP signal in the 10 colonies
transfected with the UB6 Control plasmid was 51, when measured 25
days after transfection. 60 days after transfection the average of
the d2EGFP signal in these 10 colonies was 29, indicating that the
expression was not stable over time. In comparison, the average of
the d2EGFP signal in the 10 colonies transfected with the
UB6-STAR67 plasmid was 218 when measured after 25 days and 224
measured 60 days after transfection. Hence, 25 days after
transfection, a STAR67-encompassing UB6 construct conveyed a factor
4.3 higher UB6 promoter driven expression level of the reporter
protein in stably transfected clones. After 60 days this factor was
7.7, due to instability of expression in the control colonies and
stability in the UB6-STAR67 colonies. Importantly, 25 days after
transfection, after the first measurement, selection pressure was
removed by culturing the colonies in medium without zeocin. Hence,
colonies containing the STAR67 construct are more stable over time
in the absence of selection pressure than colonies that do not
contain a STAR67 construct.
[0182] In conclusion, STAR67 increases expression from three
different, unrelated promoters.
Example 3
STAR67 Enhances the Expression Level from CMV, EF1.alpha. and UB6
Promoters in Stably Transfected PER.C6 Cells
[0183] We tested whether the presence of STAR67 adjacent of the
CMV, EF1.alpha. and UB6 promoters influences the expression level
of these promoters in another cell type than CHO cells, namely
human PER.C6 cells. The same constructs as in example 1 were
used.
Materials and Methods
Transfection, Culturing and Analysis of PER.C6 Cells
[0184] PER.C6.RTM. cells were cultured in DMEM medium+pyridoxine+9%
Foetal Bovine Serum (Non-Heat Inactivated), 8.9 mM MgCl.sub.2 100
U/ml penicillin, and 100 micrograms/ml streptomycin at 37.degree.
C./10% CO.sub.2. Cells were transfected with the plasmids using
Lipofectamine 2000 (Invitrogen) as described by the manufacturer.
Briefly, cells were seeded to 6-wells and grown overnight to 70-90%
confluence. Lipofectamine reagent was combined with plasmid DNA at
a ratio of 15 microliters per 3 microgram (e.g. for a 10 cm Petri
dish, 20 micrograms DNA and 120 microliters Lipofectamine) and
added after 30 minutes incubation at 25.degree. C. to the cells.
After 6-hour incubation the transfection mixture was replaced with
fresh medium, and the transfected cells were incubated further.
After overnight cultivation, cells were trypsinized and seeded
(1:15, 1:30, 1:60, 1:120 dilutions) into fresh petri dishes (90 mm)
with fresh medium with zeocin added to a concentration of 100
.mu.g/ml and the cells were cultured further. When colonies became
visible, individual clones were isolated by scraping and
transferred to 24-well plates in medium with zeocin. When grown to
.about.70% confluence, cells were transferred to 6-well plates.
Stable colonies were expanded for 2 weeks in 6-well plates before
the d2EGFP signal was determined on a XL-MCL Beckman Coulter
flowcytometer. The mean of the d2EGFP signal was taken as measure
for the level of d2EGFP expression. Colonies were measured for a
second time after 2 weeks. Thereafter colonies were further
cultured in the absence of zeocin.
Results
[0185] FIG. 5 shows that transfection of the construct that
contains STAR67 cloned upstream of the CMV promoter resulted in a
number of PER.C6 colonies that express significantly higher levels
of d2EGFP protein, as compared to the "empty" control without
STAR67, CMV Control. The average of the d2EGFP signal in the 10
colonies transfected with the CMV Control plasmid was 37, when
measured 30 days after transfection. 60 days after transfection the
average of the d2EGFP signal in these 10 colonies was reduced to
14, indicating that expression was not stable over time. In
comparison, the average of the d2EGFP signal in the 10 colonies
transfected with the STAR67-CMV plasmid was 101 when measured after
30 days and 45 measured 60 days after transfection. Hence 60 days
after transfection, a STAR67-encompassing CMV construct conveyed a
factor 3.2 higher CMV promoter driven expression level of the
reporter protein in stably transfected clones.
[0186] FIG. 6 shows that transfection of the construct that
contains STAR67 cloned upstream of the EF1.alpha.-promoter resulted
in a number of PER.C6 colonies that express significantly higher
levels of d2EGFP protein, as compared to the "empty" control
without STAR67, E1.alpha. Control. The average of the d2EGFP signal
in the 10 colonies transfected with the EF1.alpha. Control plasmid
was 5, when measured 30 days after transfection. 60 days after
transfection the average of the d2EGFP signal in these 10 colonies
was 6. In comparison, the average of the d2EGFP signal in the 10
colonies transfected with the EF1.alpha.-STAR67 plasmid was 25 when
measured after 30 days and 20 measured 60 days after transfection.
Hence, both after 30 and 60 days after transfection, a
STAR67-encompassing EF1.alpha. construct conveyed a factor 4 higher
EF1.alpha. promoter driven expression level of the reporter protein
in stably transfected clones.
[0187] FIG. 7 shows that transfection of the construct that
contains STAR67 cloned upstream of the UB6 promoter resulted in a
number of PER.C6 colonies that express significantly higher levels
of d2EGFP protein, as compared to the "empty" control without
STAR67, UB6 Control. The average of the d2EGFP signal in the 10
colonies transfected with the UB6 Control plasmid was 4, when
measured 30 days after transfection. 60 days after transfection the
average of the d2EGFP signal in these 10 colonies was 2. In
comparison, the average of the d2EGFP signal in the 10 colonies
transfected with the UB6-STAR67 plasmid was 27 when measured after
30 days and 18 measured 60 days after transfection. Hence, both
after 30 and 60 days after transfection, a STAR67-encompassing UB6
construct conveyed a factor 7 to 9 fold higher UB6 promoter driven
expression level of the reporter protein in stably transfected
clones.
[0188] Hence placing STAR67 upstream of the promoter resulted in
significantly higher protein expression levels in comparison with
STAR67-less constructs, also in PER.C6 cells. Hence STAR67
functions in different, unrelated cell types.
Example 4
Novel Configuration of STAR67 Combined With Other STAR Elements to
Enhance the SV40 Promoter in CHO Cells
[0189] We tested whether the presence of STAR67 adjacent of the
SV40 promoter influences the expression level of this promoter,
either alone or in combination with another STAR element, in this
example STAR7. The constructs that were used for this purpose (see
FIG. 8), are:
[0190] 1 SV40-d2EGFP-ires-Zeo (SV40 Control)
[0191] 2 STAR67-SV40-d2EGFP-ires-Zeo (SV40-STAR67)
[0192] 3 STAR7-SV40-d2EGFP-ires-Zeo-STAR7 (SV40-STAR7/7)
[0193] 4 STAR7-STAR67-SV40-d2EGFP-ires-Zeo-STAR7 (SV40-STAR67
7/7)
Materials and Methods
[0194] The SV40 promoter was amplified by PCR with pIRES as
template using primers
TTGGTTGGGGCGCGCCGCAGCACCATGGCCTGAAATAACCTCTGAAAGAGG (SEQ. ID. NO.
81) and TTGGTTGGGAGCTCAAGCTTTTTGCAAAAGCCTAGGCCTCCAAAAAAGCCTCCTC
(SEQ. ID. NO. 82). The PCR fragment was cloned in the AscI and SacI
sites of CMV-d2EGFP-IRES-Zeo, from which the CMV promoter was
removed.
[0195] CHO cells were transfected, colonies were isolated and
propagated and analysed as in Example 2.
Results
[0196] FIG. 8 shows that transfection of the construct that either
contains STAR67 cloned upstream of the SV40 promoter (SV40-STAR67)
or STAR 7 cloned to flank the entire construct (SV40-STAR 7/7) did
not result in CHO colonies that express significantly higher levels
of d2EGFP protein, as compared to the "empty" control without STARs
(SV40 Control). The average of the d2EGFP signal in the 18 colonies
transfected with the SV40 Control plasmid was 86, when measured 40
days after transfection. In comparison, the average of the d2EGFP
signal in the 18 colonies transfected with the SV40-STAR67 plasmid
was 82 when measured after 40 days and the average of the d2EGFP
signal in the 18 colonies transfected with the SV40-STAR 7/7
plasmid was 91 when measured after 40 days. Hence, no significant
effect of these STAR elements on the SV40 promoter in CHO cells was
observed.
[0197] It appears that the expression levels from the SV40 promoter
in these cells are already quite high, and even much higher than
those observed with the CMV promoter, which was considered to be a
very strong promoter. This high background expression in the
absence of a STAR element using the SV40 promoter in CHO cells, may
explain why no significant effect of STAR67 alone, or STAR7
flanking the transgene, was observed.
[0198] However, the average of the d2EGFP signal in the 18 colonies
transfected with the SV40-STAR67 7/7 plasmid was 209 when measured
after 40 days colonies, which is a factor 2.4 higher than the
average of the 18 control colonies (86). Hence, when the STAR67
element is used in combination with another STAR element, this
results in a number of stably transfected CHO colonies that show
significantly higher d2EGFP expression levels.
[0199] Therefore in this novel configuration (5'-STAR sequence
A--STAR sequence C-promoter--nucleic acid encoding a protein of
interest--STAR sequence B-3', wherein in the present example STAR
sequences A and B are STAR 7 and STAR sequence C is STAR67) STAR
elements appear to function even better than in hitherto disclosed
configurations.
[0200] We have done experiments in which the flanking STAR7
elements were replaced by flanking STAR6 elements or by flanking
STAR4 elements, in combination with STAR67 upstream of the SV40
promoter (SV40-STAR67 6/6 and SV40-STAR67 4/4, respectively, using
the same nomenclature as above), and observed improved expression
also with these combinations. This proves that the flanking STAR7
elements can indeed be exchanged for other STAR sequences, and
still the improvement of the novel configuration of the expression
cassette with the STAR sequences is observed.
Example 5
A Combination of STAR67 and STAR7 Enhance UB6-Driven Antibody
Expression Levels in Stably Transfected CHO Cells
[0201] In example 4 we showed that the combination of STAR67 and
STAR7 enhanced the expression levels of d2EGFP protein in CHO
cells. Here we tested whether the combination of STAR67 and STAR7
could be used for the production of an antibody. We chose an
antibody against the EpCAM molecule (Huls et al, 1999) as test
protein and used the UB6 promoter.
Materials and Methods
Plasmids
[0202] The heavy chain cDNA (HC-EpCAM) was cloned in a construct
encompassing the UB6 promoter. The HC-EpCAM was coupled to the
Zeocin resistance gene by an IRES sequence. The light chain cDNA
(LC-EpCAM) was also cloned in a construct encompassing the UB6
promoter. The LC-EpCAM was coupled to the puromycin resistance gene
by an IRES sequence. Together these two plasmids represent the UB6
(HC+LC) Control (FIG. 9)
[0203] To test the effects of STAR67 and STAR7, STAR67 was cloned
in both HC+LC constructs, upstream of the UB6 promoters. STAR7 was
cloned to flank the entire cassettes, both at the 5' and 3' end
(FIG. 9). These two plasmids represent STAR7-STAR67-UB6 (HC+LC)
STAR7.
Transfection and Culture of CHO Cells
[0204] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) was
transfected and cultured as in example 2, using zeocin (100
.mu.g/ml) and puromycin (2.5 .mu.g/ml) for selection. One day after
transfection, zeocin was added to the culture medium. When first
colonies became visible (approximately 7 days after addition of
zeocin) the culture medium was removed and replaced with culture
medium containing puromycin. After approximately 7 days, colonies
were isolated and transferred to 24 wells plates, in culture medium
containing zeocin only.
Results
[0205] FIG. 9 shows that that transfection of antibody constructs
that contain STAR67 cloned upstream of the UB6 promoter and two
STAR7 elements cloned to flank the entire cassettes resulted in a
number of CHO colonies that express significantly higher levels of
EpCAM antibody (measured by ELISA using an anti-human IgG antibody)
as compared to the "empty" control without STAR67 and STAR7, UB6
(HC+LC) Control. The average of the EpCAM production in the 18
colonies transfected with the UB6 (HC+LC) Control plasmid was 2.7
pg/cell/day, when measured 25 days after transfection. Selection
agents zeocin and puromycin were removed after 25 days. 45 days
after transfection the average of the EpCAM production in these 18
colonies was 2.7 pg/cell/day. In comparison, the average of the
EpCAM production signal in the 18 colonies transfected with the
STAR7-STAR67-UB6 (HC+LC)-STAR7 plasmid was 6.7 when measured after
25 days and 7.7 pg/cell/day, when measured 45 days after
transfection. Hence, both after 30 and 45 days after transfection,
a STAR67/STAR7-encompassing UB6 construct conveyed a factor 2.5 to
2.9 fold higher UB6 promoter driven EpCAM expression level in
stably transfected CHO clones.
[0206] Hence placing STAR67 upstream of the promoter and two STAR7
elements to flank the cassettes resulted in significantly higher
EpCAM antibody expression levels in CHO, in comparison with
STAR67/STAR7-less constructs.
Example 6
STAR67 is Not an Enhancer Blocker, Whereas STAR6 and STAR7 are
[0207] All hitherto known STAR elements that were tested for that
property, including STAR6 and STAR7, are enhancer blockers (WO
03/004704, Kwaks et al, 2003). Enhancer blocker activity is tested
by placing a STAR element between a strong enhancer and a promoter.
Here we tested whether also STAR67 is an enhancer blocker.
Materials and Methods
[0208] The d2EGFP gene was PCR-amplified using primers
TTGGTTGGTCATGAATGGTGAGCAAGGGCGAGGAGCTGTTC (SEQ.ID.NO. 75) and
ATTCTCTAGACTACACATTGATCCTAGCAGAAGCAC (SEQ.ID.NO. 76) and cloned
into plasmid pGL3-promoter (Promega) using the NcoI and XbaI
restriction sites to replace the Luciferase gene to create plasmid
pGL3-promoter-GFP. A linker (created by annealing oligo's
CGATATCTTGGAGATCTACTAGTGGCGCGCCTTGGGCTAGCT (SEQ.ID.NO. 77) and
GATCAGCTAGCCCAAGGCGCGCCACTAGTAGATCTCCAAGATATCGAGCT (SEQ.ID.NO. 78),
was cloned in the SacI and BglII sites to create multiple cloning
sites. The original BglII site was destroyed upon ligation of the
linker, creating a new unique BglII site within the linker DNA. The
SV40-enhancer was cut from plasmid pGL3-basic (Promega) using BsaBI
and BamHI and cloned into the pGL3-linker-promoter-GFP using the
EcoRV and BglII sites creating plasmid pGL3-enhancer-promoter-GFP.
The STAR40 element was placed upstream of the SV40 enhancer using
KpnI and SacI sites to prevent action of the enhancer on upstream
sequences. Finally, STAR elements 6, 7 and 67 were placed in
between the SV40 enhancer and the SV40 minimal promoter using the
SpeI and AscI restriction sites.
Transfection and Culture of CHO Cells
[0209] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) is
transfected as in example 2. One day after the transfection, d2EGFP
levels are measured on an Epics XL flowcytometer (Beckman
Coulter)
Results
[0210] FIG. 10 shows that STAR67 is not an enhancer blocker,
whereas STAR6 and STAR7 act enhancer blockers in the same assay.
STAR6, STAR7 and STAR67 were cloned between the SV40 enhancer and a
minimal SV40-promoter upstream of the d2EGFP gene. When no STAR
element was cloned between the enhancer and the promoter strong
transcriptional activation occurred (arbitrarily set at 100%). When
STAR6 or STAR7 was placed between the enhancer and the promoter,
transcription dropped to background levels, indicating that STAR6
and STAR7 are potent enhancer blockers. In contrast, when STAR67
was cloned between the enhancer and the promoter relative
transcription levels were still 80% of the control, indicating that
STAR67 is not a good enhancer blocker, this in contrast with STAR6
and STAR 7, as well as other STAR elements, as previously described
(WO 03/004704, Kwaks et al, 2003).
Example 7
STAR67 Enhances UB6 and CMV-Driven Antibody Expression Levels in
Stably Transfected CHO Cells
[0211] In example 5 we showed that the combination of STAR67 and
STAR7 enhanced the expression levels of EpCAM antibody in CHO
cells, in the context of two distinct plasmids, which contained the
heavy and light chains. In this example we tested whether STAR67
could be used for the production of EpCAM antibody when both heavy
and light chains are placed on one plasmid. We used simultaneous
selection for each selectable marker.
Materials and Methods
Plasmids
[0212] The heavy chain cDNA (HC-EpCAM) is under the control of the
UB6 promoter and coupled to the Zeocin resistance gene by an IRES
sequence. The light chain cDNA (LC-EpCAM) is under control of the
CMV promoter and coupled to the puromycin resistance gene by an
IRES sequence. Basically these are the constructs used in example
5. These two expression cassettes were placed on one plasmid, in
such a manner that transcription of the two expression units had
opposite directions. In the control plasmid the UB6 and CMV
promoters were separated by a stuffer of 500 bp(EpCAM Control)
(FIG. 10). In another plasmid STAR67 was placed between the UB6 and
CMV promoter (EpCAM STAR67) (FIG. 10).
Transfection and Culture of CHO Cells
[0213] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) was
transfected and cultured as in example 2, using zeocin (100
.mu.g/ml) and puromycin (2.5 .mu.g/ml) for selection. In example 5,
consecutive selection for both selection markers was used. In
contrast, here both selection agents were present in the culture
medium simultaneously. One day after transfection, zeocin and
puromycin were added to the culture medium. The selection medium
was present until colonies were isolated (approximately 14 days
after transfection). After colonies were isolated and transferred
to 24-wells plates, the cells were cultured in the presence of
zeocin and puromycin.
Results
[0214] FIG. 11 shows that that transfection of the antibody
construct that contains STAR67 cloned between the UB6 and CMV
promoters resulted in a number of CHO colonies that express EpCAM
antibody (measured by ELISA using an anti-human IgG antibody). The
average of the EpCAM production in the 19 colonies transfected with
the EpCAM STAR67 plasmid was 9.8 pg/cell/day, when measured 25 days
after transfection.
[0215] In contrast, surprisingly no colonies survived of the
transfection with the EpCAM Control plasmid. When selection was
performed with either zeocin or puromycin alone, EpCAM Control
colonies survived. However, when the selection pressure was
increased by placing selection pressure on both the heavy and light
chain, these conditions allowed only colonies to survive that have
a STAR67 present in the transfected plasmid.
[0216] The results also show that incorporation of STAR67 has a
beneficial effect on two promoters, the UB6 and CMV promoters, that
are placed upstream and downstream of one STAR67 element. This
indicates that STAR67 may operate in a bi-directional fashion.
[0217] The difference between the EpCAM control and EpCAM STAR67
plasmid is black-white in the sense that only transfection of EpCAM
STAR67 results in the establishment of colonies, when the selection
pressure is high. This opens an opportunity to use this plasmid
configuration for identifying the region in STAR67 that is
responsible for mediating this effect. Smaller, overlapping
portions of STAR67 are placed between the UB6 and CMV promoters,
driving the EpCAM molecule. When a portion of STAR67 is functional,
colonies will survive when both zeocin and puromycin are
simultaneously used as selection agent. When a portion of STAR67 is
not functional, no colonies will survive under identical selection
conditions.
[0218] Hence placing STAR67 upstream of the promoter resulted in
significantly higher EpCAM antibody expression levels in CHO, in
comparison with STAR-less constructs.
Example 8
Construction and Testing of a Zeocin Resistance Gene Product with
No Internal Methionine
[0219] The basic idea behind the development of a novel selection
system is to place the gene encoding the resistance gene upstream
of a gene of interest, and one promoter drives the expression of
this bicistronic mRNA. The translation of the bicistronic mRNA is
such that only in a small percentage of translation events the
resistance gene will be translated into protein and that most of
the time the downstream gene of interest will be translated into
protein. Hence the translation efficiency of the upstream
resistance gene must be severely hampered in comparison to the
translation efficiency of the downstream gene of interest. To
achieve this, three steps can be taken according to the
invention:
[0220] 1) within the resistance gene on the mRNA, the searching
ribosome preferably should not meet another AUG, since any
downstream AUG may serve as translation start codon, resulting in a
lower translation efficiency of the second, downstream gene of
interest. Hence, preferably any AUG in the resistance gene mRNA
will have to be replaced. In case this AUG is a functional codon
that encodes a methionine, this amino acid will have to be replaced
by a different amino acid, for instance by a leucine (FIG. 12A and
B);
[0221] 2) the start codon of the resistance gene must have a bad
context (be part of a non-optimal translation start sequence); i.e.
the ribosomes must start translation at this start codon only in a
limited number of events, and hence in most events continue to
search for a better, more optimal start codon (FIG. 12C-E). Three
different stringencies can be distinguished: a) the normal ATG
startcodon, but placed in a bad context (TTTATGT) (called ATGmut)
(FIG. 12C), b) preferably when placed in an optimal context, GTG
can serve as startcodon (ACCGTGG) (FIG. 12D) and c) preferably when
placed in an optimal context, TTG can serve as startcodon (ACCTTGG)
(FIG. 12E). The most stringent translation condition is the TTG
codon, followed by the GTG codon (FIG. 12). The Zeo mRNA with a TTG
as start codon is expected to produce the least Zeocin resistance
protein and will hence convey the lowest functional Zeocin
resistance to cells (FIGS. 12, 13).
[0222] 3) preferably, the normal start codon (ATG) of the
downstream gene of interest should have an optimal translation
context (e.g. ACCATGG)(FIG. 13A-D). This warrants that, after steps
1 and 2 have been taken, in most events the start codon of the gene
of interest will function as start codon of the bicistronic
mRNA.
[0223] In example 8, step 1 is performed, that is, in the Zeocin
resistance gene one existing internal methionine is replaced by
another amino acid (FIG. 12B-E). It is important that after such a
change the Zeo protein still confers Zeocin resistance to the
transfected cells. Since it is not known beforehand which amino
acid will fulfill this criterium, three different amino acids have
been tried: leucine, threonine and valine. The different constructs
with distinct amino acids have than been tested for their ability
to still confer Zeocin resistance to the transfected cells.
Materials and Methods
Construction of the Plasmids
[0224] The original Zeo open reading frame has the following
sequence around the startcodon: AAACCATGGCC (startcodon in bold;
SEQ. ID. NO. 83). This is a startcodon with an optimal
translational context (FIG. 12A). First the optimal context of the
start codon of the Zeo open reading frame was changed through
amplification from plasmid pCMV-zeo [Invitrogen V50120], with
primer pair ZEOforwardMUT (SEQ. ID. NO. 84):
GATCTCGCGATACAGGATTTATGTTGGCCAAGTTGACCAGTGCCGTTCCG and
ZEO-WTreverse (WT=Wild type; SEQ. ID. NO. 85):
AGGCGAATTCAGTCCTGCTCCTCGGC, using pCMV-ZEO (Invitrogen; V50120) as
a template. The amplified product was cut with NruI-EcoRI, and
ligated into pcDNA3, resulting in pZEOATGmut.
[0225] The original Zeo open reading frame contains an in frame
ATG, encoding methionine at amino acid position 94 (out of 124).
This internal ATG, encoding the methionine at position 94 was
changed in such a way that the methionine was changed into leucine,
threonine or valine respectively:
[0226] 1) To replace the internal codon for methionine in the Zeo
open reading frame with the codon for leucine (FIG. 12B), part of
the Zeo open reading frame was amplified using primer pair
ZEOforwardMUT (SEQ. ID. NO. 84) and ZEO-LEUreverse (SEQ. ID. NO.
86): AGGCCCCGCCCCCACGGCTGCTCGCCGATCTCGGTCAAGGCCGGC. The PCR product
was cut with BamHI-BglI and ligated into pZEOATGmut. This resulted
in pZEO(leu). To replace the internal codon for methionine in the
Zeo open reading frame with the codon for threonine (not shown, but
as in FIG. 12B), part of the Zeo open reading frame was amplified
using primer pair ZEOforwardMUT (SEQ. ID. NO. 84) and
ZEO-THRreverse (SEQ. ID. NO. 87):
AGGCCCCGCCCCCACGGCTGCTCGCCGATCTCGGTGGTGGCCGGC. The PCR product was
cut with BamHI-BglI and ligated into pZEOATGmut. This resulted in
pZEO(thr). To replace the internal codon for methionine in the Zeo
open reading frame with the codon for valine (not shown, but as in
FIG. 12B)(GTG), part of the Zeo open reading frame was amplified
using primer pair ZEOforwardMUT (SEQ. ID. NO. 84) and
ZEO-VALreverse (SEQ. ID. NO. 88):
AGGCCCCGCCCCCACGGCTGCTCGCCGATCTCGGTCCACGCCGG. The PCR product was
cut with BamHI-BglI and ligated into pZEOATGmut. This resulted in
pZEO(val).
Transfection and Culturing of Cells
[0227] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) was
cultured in HAMS-F12 medium+10% Fetal Calf Serum containing 2 mM
glutamine, 100 U/ml penicillin, and 100 micrograms/ml streptomycin
at 37.degree. C./5% CO.sub.2. Cells were transfected with the
plasmids using Lipofectamine 2000 (Invitrogen) as described by the
manufacturer. Briefly, cells were seeded to culture vessels and
grown overnight to 70-90% confluence. Lipofectamine reagent was
combined with plasmid DNA at a ratio of 6 microliters per microgram
(e.g. for a 10 cm Petri dish, 20 micrograms DNA and 120 microliters
Lipofectamine) and added to the cells. After overnight incubation
the transfection mixture was replaced with fresh medium, and the
transfected cells were incubated further. After overnight
cultivation, cells were trypsinized and seeded into fresh culture
vessels with fresh medium containing zeocin (100 .mu.g/ml). When
individual colonies became visible (approximately ten days after
transfection) colonies were counted.
Results
[0228] Four plasmids were transfected to CHO-K1 cells, 1) pZEO(WT),
2) pZEO(leu), 3) pZEO(thr), and 4) pZEO(val). The cells were
selected on 100 .mu.g/ml zeocine. Transfection of pZEO(leu)
resulted in an equal number of zeocin resistant colonies in
comparison with the control pZEO (WT). pZEO(thr) and pZEO(val) gave
less colonies, but the differences were not in the order of a
magnitude. Hence it was concluded that changes of the internal
methionine into leucine, threonine or valine all resulted in a
Zeocin resistance protein that is still able to confer zeocin
resistance to the transfected cells. Rather arbitrarily, pZEO(leu)
was chosen as starting point for creating different startcodons on
the Zeo open reading frame. Hence in the examples below the start
as well as internal methionines are always replaced by leucine, for
zeocin, but also for other selectable marker genes, as will be
clear from further examples.
Example 9
Creation and Testing of Zeocin-d2EGFP Bicistronic Constructs with
Differential Translation Efficiencies
[0229] To create a bicistronic mRNA encompassing a mutated Zeocin
resistance mRNA with less translational efficiency, and the d2EGFP
gene as downstream gene of interest, the start codon of the d2EGFP
gene was first optimized (step 3 in example 8). After that, the
different versions of the Zeocin resistance gene were created. The
differences between these versions are that they have different
start codons, with distinct translational efficiency (step 2 in
Example 9, FIG. 12C-E). These different Zeocin resistance gene
versions were cloned upstream of the modified d2EGFP gene (FIG.
13).
Materials and Methods
Creation of Plasmids
[0230] The d2EGFP reporter ORF was introduced into pcDNA3. The
sequence around the startcodon of this d2EGFP cDNA is GAATTCATGGG
(startcodon in bold; SEQ. ID. NO. 89), which is not optimal. As a
first step, d2EGFP was amplified from pd2EGFP (Clontech 6010-1)
with primers d2EGFPforwardBamHI (SEQ. ID. NO. 90):
GATCGGATCCTATGAGGAATTCGCCACCATGGTGAGCAAGGGCGAGGAG and
d2EGFPreverseNotI (SEQ. ID. NO. 91):
AAGGAAAAAAGCGGCCGCCTACACATTGATCCTAGCAGAAG. This product contains
now a startcodon with an optimal translational context (ACCATGG).
This created pd2EGFP and subsequently, the Zeo open reading frame
was ligated into pd2EGFP, resulting in pZEO-d2EGFP. It is pointed
out here that the optimization of the translational start sequence
of the gene of interest (here: EGFP as a model gene) is not
essential but preferred in order to skew the translation initiation
frequency towards the gene of interest still further.
[0231] Now Three Classes of Constructs were Made:
[0232] 1) ATG as a start codon in the Zeo resistance gene, but in a
bad context (TTTATGT) (not shown, but as in FIG. 13B) and followed
by spacer sequence, instead of the optimal ATG (FIG. 13A). The
spacer sequence is placed downstream of the ATG sequence. In the
zeocin (and possibly in the blasticidin) RNA, a secondary structure
is present, causing the ribosome to be temporarily delayed. Because
of this, a poor startcodon can in some cases be used by the
ribosome, despite being a bad startcodon or being in a non-optimal
context for translation initiation. This causes the chance of
translation to increase, and in case of the current invention
therefore renders the stringency for selection lower. To decrease
this effect, and hence to further decrease the translation
initation efficiency, a spacer sequence is introduced that does not
contain a secondary structure (Kozak, 1990). Hence, the term
`space` is introduced, and used in the plasmid and primer names to
indicate the presence of such a spacer sequence. The spacer removes
the `ribosome delaying sequence` from the neighbourhoud of the
initiation codon, therewith causing the ribosome to start
translating less frequently, and hence increasing the stringency of
the selection according to the invention. The spacer introduces
some extra amino acids in the coding sequence. This has been done
in some cases for both zeocin and for blasticidin, as will be
apparent from the examples. The nomenclature of the plasmids and
primers in general in the following is along these lines: the name
of the selectable marker polypeptide is referred to by abbreviation
(e.g. Zeo, Blas, etc); the startcodon is mentioned (e.g. ATG, GTG,
TTG); when this startcodon is placed in a non-optimal context for
translation initiation, the addition "mut" is used (this is usually
only done for ATG startcodons, as combining a non-optimal context
with a non-ATG startcodon usually does not result in sufficient
translation initiation to allow for selection); when a spacer
sequence is used behind the startcodon, the addition "space" is
used (this is done usually for "ATGmut" startcodons for Zeo or Blas
selectable markers). The Zeo open reading frame was amplified with
primer pair ZEOforwardBamHI-ATGmut/space (SEQ. ID. NO. 93):
GATCGGATCCTTGGTTTATGTCGATCCAAAGACTGCCAAATCTAGATCCGAGATTTTC
AGGAGCTAAGGAAGCTAAAGCCAAGTTGACCAGTGAAGTTC (wherein the sequence
following the underlined sequence comprises the spacer sequence),
and ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was cut with
EcoRI-BamHI, and ligated into pd2EGF, cut with EcoRI-BamHI,
creating pZEO-ATGmut/space-d2EGFP.
[0233] 2) GTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 13C). The Zeo open reading frame was amplified with
primer pair ZEOforwardBamHI-GTG (SEQ. ID. NO. 94):
GATCGGATCCACCGTGGCCAAGTTGACCAGTGCCGTTC and ZEOWTreverse (SEQ. ID.
NO. 85), the PCR product was cut with EcoRI-BamHI, and ligated into
pd2EGFP, cut with EcoRI-BamHI, creating pZEO-GTG-d2EGFP.
[0234] 3) TTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 13D). The Zeo open reading frame was amplified with
primer pair ZEOforwardBamHI-TTG:
GATCGGATCCACCTTGGCCAAGTTGACCAGTGCCGTTC (SEQ. ID. NO. 95) and
ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was cut with
EcoRI-BamHI, and ligated into pd2EGFP, cut with EcoRI-BamHI,
creating pZEO-TTG-d2EGFP.
Transfection, Culturing and Analysis of CHO Cells
[0235] The Chinese Hamster Ovary cell line CHO-K1 (ATCC CCL-61) was
cultured in HAMS-F12 medium+10% Fetal Calf Serum containing 2 mM
glutamine, 100 U/ml penicillin, and 100 micrograms/ml streptomycin
at 37.degree. C./5% CO.sub.2. Cells were transfected with the
plasmids using Lipofectamine 2000 (Invitrogen) as described by the
manufacturer. Briefly, cells were seeded to culture vessels and
grown overnight to 70-90% confluence. Lipofectamine reagent was
combined with plasmid DNA at a ratio of 15 microliters per 3
microgram (e.g. for a 10 cm Petri dish, 20 micrograms DNA and 120
microliters Lipofectamine) and added after 30 minutes incubation at
25.degree. C. to the cells. After overnight incubation the
transfection mixture was replaced with fresh medium, and the
transfected cells were incubated further. After overnight
cultivation, cells were trypsinized and seeded into fresh culture
vessels with fresh medium. After another overnight incubation
zeocin was added to a concentration of 50 .mu.g/ml and the cells
were cultured further. After another three days the medium was
replaced by fresh medium containing zeocin (100 .mu.g/ml) and
cultured further. When individual colonies became visible
(approximately ten days after transfection) medium was removed and
replaced with fresh medium without zeocin. Individual clones were
isolated and transferred to 24-well plates in medium without
zeocin. One day after isolation of the colonies zeocin was added to
the medium. Expression of the d2EGFP reporter gene was assessed
approximately 3 weeks after transfection. d2EGFP expression levels
in the colonies were measured after periods of two weeks.
Results
[0236] CHO-K1 cells were transfected with constructs that contain
the ATGmut/space Zeo (FIG. 13B), GTG Zeo (FIG. 13C) and TTG Zeo
(FIG. 13D) genes as selection gene, all being cloned upstream of
the d2EGFP reporter gene. These three constructs were without STAR
elements (Control) or with STAR elements 7 and 67 upstream of the
CMV promoter and STAR 7 downstream from the d2EGFP gene (FIG. 14).
FIG. 14 shows that both the control (without STAR elements)
constructs with ATGmut/space Zeo (A) and GTG Zeo (B) gave colonies
that expressed d2EGFP protein. The average d2EGFP expression level
of 24 ATGmut/space Zeo colonies was 46 and of GTG Zeo colonies was
75. This higher average expression level in GTG Zeo colonies may
reflect the higher stringency of GTG, in comparison with
ATGmut/space (example 8). Addition of STAR elements 7 and 67 to the
constructs resulted in colonies that had higher average d2EGFP
expression levels. Transfection of the ATGmut/space Zeo STAR 7/67/7
construct resulted in colonies with an average d2EGFP expression
level of 118, which is a factor 2.6 higher than the average in the
control cells (46). Addition of STAR elements to the GTG Zeo
construct resulted in an average d2EGFP expression level of 99,
which is a factor 1.3 higher than the average in the control cells
(75).
[0237] Importantly, no colonies were established when the TTG Zeo
construct was transfected. However, the construct with TTG Zeo,
flanked with STARs 7 and 67 resulted in the establishment of 6
colonies, with an average d2EGFP expression level of 576 (FIG.
14C). Thus the highest translation stringency, brought about by the
TTG startcodon (FIG. 12) yields to the highest d2EGFP expression
levels, as predicted in FIG. 13. The results also indicate that the
stringency of the TTG Zeo alone (without STAR elements) is at least
in some experiments too high for colonies to survive. However, in
later independent experiments (see below), some colonies were found
with this construct without STAR elements, indicating that the
stringency of the selection system with the TTG startcodon in the
zeocin selection marker not necessarily precludes the finding of
colonies when no STAR elements are present, and that the number of
colonies obtained may vary between experiments.
[0238] It is concluded that the use of STAR elements in combination
with the stringent selection system according to the invention
allows to readily identify high producers of the gene of
interest.
Example 10
Establishment of a Higher Number of TTG Zeo STAR Colonies and
Comparison with an IRES-Zeo Construct
[0239] The results in example 9 indicate that the TTG Zeo has
extremely stringent translation efficiency, which might be to high
to convey Zeocin resistance to the cells. The transfection was
scaled up to test whether there would be some colonies that have
such high expression levels that they survive. Scaling up the
experiment could also address the question whether the high average
of TTG Zeo STAR 7/67/7 would become higher when more colonies were
analyzed.
Materials and Methods
[0240] CHO-K1 cells were transfected with the constructs that have
the TTG Zeo gene as selection marker, with and without STAR
elements 7 and 67 (FIG. 15). Transfections, selection, culturing
etc were as in example 9, except that 6 times more cells, DNA and
Lipofectamine 2000 were used. Transfections and selection were done
in Petri dishes.
Results
[0241] FIG. 15A shows that transfection with the TTG Zeo STAR
7/67/7 construct resulted in the generation of many colonies with
an average d2EGFP signal of 560. This is as high as in example 9,
except that now 58 colonies were analyzed. When compared to a
construct with the Zeocin resistance gene placed behind an IRES
sequence (FIG. 15B), the average d2EGFP expression level was 61,
and when STAR elements 7 and 67 were added to such a construct, the
average d2EGFP expression level was 125, a factor 2 above the
control (FIG. 15B). The average of the TTG Zeo STAR 7/67/7 colonies
was therefore a factor 9.2 higher than the STAR-less IRES-Zeo
colonies and a factor 4.5 higher than the STAR7/67/7 IRES Zeo
colonies.
[0242] An observation is that the form of the curve of all
expressing colonies differs between the TTG Zeo STAR7/67/7 and
IRES-Zeo STAR 7/67/7. In the first case (TTG Zeo) the curve levels
off, whereas in the second case (IRES-Zeo) the curve has a more
`exponential` shape. The plateau in the TTG Zeo curve could
indicate that the cells have reached a maximum d2EGFP expression
level, above which the d2EGFP expression levels become toxic and
the cells die. However, it later appeared that the high values were
close to the maximum value that could be detected with the settings
of the detector of the FACS analyser. In later experiments, the
settings of the FACS analyser were changed to allow for detection
of higher values, and indeed in some instances higher values than
obtained here were measured in later independent experiments (see
below).
[0243] Due to up-scaling of the transfections three colonies with
the STAR-less TTG Zeo construct could be picked. The d2EGFP
expression levels of these colonies were 475, 158 and 43. The last
colony died soon after the first measurement. This result indicates
that the TTG Zeo construct can convey Zeocin resistance, resulting
in colonies that also can give high expression levels in some
instances. Hence, the novel selection method according to the
invention can be applied with expression cassettes that do not
contain chromatin control elements, although it is clearly
preferred to use expression cassettes comprising at least one such
element, preferably a STAR element.
[0244] The results indicate that STAR elements allow a more
stringent selection system according to the invention, such as
exemplified in this example, resulting in the picking of colonies
that have a very high average protein expression level.
Example 11
Creation and Testing of Blasticidin-d2EGFP Bicistronic Constructs
with Differential Translation Efficiencies
[0245] There are four internal ATGs in the blasticidine resistance
gene, none of which codes for a methionine (FIG. 25A). These ATGs
have to be eliminated though (FIG. 25B), since they will serve as
start codon when the ATG startcodon (or the context thereof) has
been modified, and this will result in peptides that do not
resemble blasticidine resistance protein. More importantly, these
ATGs will prevent efficient translation of the gene of interest, as
represented by d2EGFP in this example for purposes of illustration.
To eliminate the internal ATGs, the blasticidine resistance protein
open reading frame was first amplified with 4 primer pairs,
generating 4 blasticidine resistance protein fragments. The primer
pairs were: TABLE-US-00001 A) BSDBamHIforward (SEQ. ID. NO. 96):
GATCGGATCCACCATGGCCAAGCCTTTGTCTCAAG BSD150reverse (SEQ. ID. NO.
97): GTAAAATGATATACGTTGACACCAG B) BSD150forward (SEQ. ID. NO. 98):
CTGGTGTCAACGTATATCATTTTAC BSD250reverse (SEQ. ID. NO. 99):
GCCCTGTTCTCGTTTCCGATCGCG C) BSD250forward (SEQ. ID. NO. 100):
CGCGATCGGAAACGAGAACAGGGC BSD350reverse (SEQ. ID. NO. 101):
GCCGTCGGCTGTCCGTCACTGTCC D) BSD350forward (SEQ. ID. NO. 102):
GGACAGTGACGGACAGCCGACGGC BSD399reverse (SEQ. ID. NO. 103):
GATCGAATTCTTAGCCCTCCCACACGTAACCAGAGGGC
[0246] Fragments A to D were isolated from an agarose gel and mixed
together. Next, only primers BSDBamHIforward and BSD399reverse were
used to create the full length blasticidine resistance protein
cDNA, but with all internal ATGs replaced. The reconstituted
blasticidine was then cut with EcoRI-BamHI, and cloned into
pZEO-GTG-d2EGFP, cut with EcoRI-BamHI (which releases Zeo),
resulting in pBSDmut-d2EGFP. The entire blasticidine resistance
protein open reading frame was sequenced to verify that all ATGs
were replaced.
[0247] With this mutated gene encoding blasticidine resistance
protein (Blas), three classes of constructs are made (FIG.
25C-E):
[0248] 1) ATG as a start codon, but in a bad context and followed
by spacer sequence. The mutated blasticidine resistance protein
open reading frame in pBSD-d2EGFP was amplified using primers
BSDforwardBamHIAvrII-ATGmut/space (SEQ. ID. NO. 104):
GATCGGATCCTAGGTTGGTTTATGTCGATCCAAAGACTGCCAAATCTAGATCCGAGA
TTTTCAGGAGCTAAGGAAGCTAAAGCCAAGCCTTTGTCTCAAGAAG, and
BSD399reverseEcoRIAvrII (SEQ. ID. NO. 105):
GATCGAATTCCCTAGGTTAGCCCTCCCACACGTAACCAGAGGGC, the PCR product is
cut with BamHI-EcoRI, and ligated into pZEO-GTG-d2EGFP, cut with
EcoRI-BamHI. This results in pBSD-ATGmut/space-d2EGFP.
[0249] 2) GTG as a start codon instead of ATG. The mutated
blasticidine resistance protein open reading frame in pBSD-d2EGFP
was amplified using primers BSDforwardBamHIAvrII-GTG (SEQ. ID. NO.
106): GATCGGATCCTAGGACCGTGGCCAAGCCTTTGTCTCAAGAAG and
BSD399reverseEcoRIAvrII (SEQ. ID. NO. 105), the PCR product was cut
with BamHI-EcoRI, and ligated into pZEO-GTG-d2EGFP, cut with
EcoRI-BamHI. This results in pBSD-GTG-d2EGFP.
[0250] 3) TTG as a start codon instead of ATG. The mutated
blasticidine open reading frame in pBSD-d2EGFP was amplified using
primers BSDforwardBamHIAvrII-TTG (SEQ. ID. NO. 107):
GATCGGATCCTAGGACCTTGGCCAAGCCTTTGTCTCAAGAAG and
BSD399reverseEcoRIAvrII (SEQ. ID. NO.105), the PCR product was cut
with BamHI-EcoRI, and ligated into pZEO-GTG-d2EGFP, cut with
EcoRI-BamHI. This results in pBSD-TTG-d2EGFP.
Results
[0251] CHO-K1 cells were transfected with constructs that contain
the GTG Bias (FIG. 16A) and TTG Blas (FIG. 16B) genes as selection
gene, all being cloned upstream of the d2EGFP reporter gene.
Selection took place in the presence of 20 .mu.g/ml Blasticidine.
The two constructs were without STAR elements (Control) or with
STAR elements 7 and 67 upstream of the CMV promoter and STAR7
downstream from the d2EGFP gene (FIG. 16). FIG. 16 shows that both
the control (without STAR elements) constructs with GTG Bias (A)
and TTG Bias (B) gave colonies that expressed d2EGFP protein. The
average d2EGFP signal of 24 GTG Bias colonies was 14.0 (FIG. 16A)
and of TTG Bias colonies was 81 (FIG. 16B). This higher average
expression level in TTG Bias colonies may reflect the higher
stringency of TTG, in comparison with GTG (see also example 9).
However, only 8 colonies survived under the more stringent TTG
conditions.
[0252] Addition of STAR elements 7 and 67 to the constructs
resulted in colonies that had higher average d2EGFP expression
levels. Transfection of the GTG Bias STAR 7/67/7 construct resulted
in colonies with an average d2EGFP expression level of 97.2 (FIG.
16A), which is a factor 6.9 higher than the average in the control
cells (14.0). Addition of STAR elements to the TTG Bias construct
resulted in an average d2EGFP signal of 234.2 (FIG. 16B), which is
a factor 2.9 higher than the average in the control cells (81).
However, note again that only 8 colonies survived the harsh
selection conditions of TTG Bias, whereas 48 colonies survived with
TTG Bias STAR 7/67/7. When only the five highest values are
compared, the average of the five highest TTG Bias was 109.1 and
the average of the five highest TTG Blas STAR 7/67/7 was 561.2,
which is a factor 5.1 higher.
[0253] The results indicate that STAR elements allow a more
stringent selection system, resulting in the picking of colonies
that have a very high average protein expression level. They also
show that this selection is not restricted to the Zeocin resistance
protein alone, but that also other selection marker polypeptides,
in this case the blasticidine resistance protein, can be used.
Example 12
Stability of d2EGFP Expression in the Novel Selection System
[0254] Colonies described in example 10 were further cultured under
several conditions to assess the stability of d2EGFP expression
over an extended time period.
Results
[0255] The TTG Zeo STAR 7/67/7 containing colonies in FIG. 15A were
cultured for an additional 70 days in the presence of 100 .mu.g/ml
Zeocin. As shown in FIG. 17, the average d2EGFP signal rose from
560.2 after 35 days to 677.2 after 105 days. Except for some rare
colonies all colonies had a higher d2EGFP expression level.
[0256] When the level of Zeocin was lowered to 20 .mu.g/ml Zeocin,
there was still an increase in the average d2EGFP expression level,
from 560.2 after 35 days to 604.5 after 105 days (FIG. 18).
[0257] When no selection pressure was present at all due to removal
of the Zeocin from the culture medium, approximately 50% of the
colonies became mosaic, that is, within one colony non-d2EGFP
expressing cells became apparent. This resulted in lowering of
d2EGFP expression levels to less than 50% of the original levels.
If the signal became less than 67% (decrease of at least one-third)
from the original signal, the colony was considered to be unstable
in respect to d2EGFP expression. Of the 57 original colonies 27
colonies remained stable according to this criterion; the average
d2EGFP signal of these colonies after 35 days (while still under
selection pressure) was 425.6, whereas the average d2EGFP signal
without selection pressure after 65 days was 290.0. When measured
after 105 days, the average signal in the 27 colonies was 300.9.
Hence, after an initial decrease, the expression levels in the 27
colonies remained stable according to this criterion (FIG. 19).
[0258] Six of the colonies were subjected to one round of
sub-cloning. Cells were sown in 96-wells plates as such that each
well contained approximately 0.3 cells. No Zeocin was present in
the medium so that from the start the sub clones grew without
selection pressure. Of each original colony six sub clones were
randomly isolated and grown in 6-wells plates till analysis. In
FIG. 23 we compared the original values of the original clones, as
already shown in FIG. 15A, with one of the sub clones. In one of
the six clones (clone 25), no sub clone was present with d2EGFP
signal in the range of the original clone. However, in five out of
six cases at least one the sub clones had equal d2EGFP expression
levels as the parent clone. These expression levels were determined
after 50 days without selection pressure. We conclude that one
round of sub cloning is sufficient to obtain a high number of
colonies that remain stable for high expression in the absence of
selection pressure. This has been confirmed in a similar experiment
(not shown).
[0259] We compared the number of copies that integrated in the TTG
Zeo STAR 7/67/7 colonies. DNA was isolated when colonies were 105
days under Zeocin selection pressure (see FIG. 17). As shown in
FIG. 24 two populations could be distinguished. In FIG. 24 the cut
off was made at 20 copies and the R.sup.2 value is calculated and
shown. Also the R.sup.2 value from data with higher than 20 copies
is shown. In the range from 100 to 800 d2EGFP signal there was a
high degree of copy number dependency, as signified by a relatively
high R.sup.2 of 0.5685 (FIG. 24). However, in the population of
colonies that fluctuate around a d2EGFP signal of 800 a high
variation in copy number was observed (FIG. 24), as signified with
a low R.sup.2 of 0.0328. Together the data show that in the novel
selection system, in colonies that contain TTG Zeo STAR 7/67/7
constructs there is copy number dependent d2EGFP expression up to
.about.20 copies. Also, although copy number dependency is lost
when >20 copies are present, still a substantial proportion of
the colonies with high (>800) d2EGFP signal have no more than 30
copies (FIG. 24). This combination between high d2EGFP expression
and a relatively low copy number (between 10 and 30) may be
important for identifying colonies that remain relatively stable
without selection pressure. It is an advantage to have clones with
relatively low copy numbers (less than about 30, more preferably
less than about 20) that give high expression levels, because such
clones are believed to be less amenable to genetic instability. The
present selection system allows to generate such clones, including
from CHO cells.
Example 13
Creation and Testing of Zeocin-Blasticidin-EpCAM Bicistronic
Constructs with Differential Translation Efficiencies
[0260] To test the selection system on the production of an
antibody, the anti-EpCAM antibody (see also example 5) was taken as
example.
Results
[0261] A plasmid was created on which both the heavy chain (HC) and
light chain (LC) were placed, each in a separate transcription unit
(FIG. 20-22). Expression of both chains was driven by the CMV
promoter. Upstream of the EpCAM heavy chain the Zeocin resistance
gene was placed, either with the ATGmut/space (FIG. 20), GTG (FIG.
21) or TTG (FIG. 22) as startcodon (see example 9). Upstream of the
EpCAM light chain the Blasticidine resistance gene was placed,
either with the ATGmut/space (FIG. 20), GTG (FIG. 21) or TTG (FIG.
22) as startcodon (see example 11). Two types of constructs were
made, one construct without STAR elements (Control) and one
construct with a combination of STAR 7 and 67 elements. The STAR
elements were placed as follows: upstream of each CMV promoter
(i.e. one for the transcription unit comprising HC and one for the
transcription unit comprising LC) STAR 67 was placed and the
resulting construct was flanked with a 5' and 3' STAR 7 element
(FIGS. 20-22). All constructs were transfected to CHO-K1 cells and
selected on 100 .mu.g/ml Zeocin and 20 .mu.g/ml Blasticidin (at the
same time). After selection independent colonies were isolated and
propagated under continuous selection pressure (using 100 .mu.g/ml
zeocin and 20 .mu.g/ml blasticidin). FIG. 20 shows that the STAR
7/67/7 combination had a beneficial effect on EpCAM production. The
ATGmut/space Zeo and ATGmut/space Blas had no effect on the number
of colonies that were formed with plasmids containing STAR elements
or not. However, the average EpCAM expression levels of either 24
control versus STAR 7/67/7 colonies ranged from 0.61 pg/cell/day in
the control to 3.44 pg/cell/day in the STAR7/67/7 construct (FIG.
20). This is a factor 5.6 increase. Since there were many colonies
in the ATGmut/space control with 0 pg/cell/day, also the average
EpCAM production in the highest five colonies was compared. In the
control ATGmut/space this was 3.0 pg/cell/day, versus 7.8
pg/cell/day with the ATGmut/space STAR 7/67/7 construct, an
increase of a factor 2.6.
[0262] FIG. 21 also shows that the STAR 7/67/7 combination had a
beneficial effect on EpCAM production, using the GTG startcodon for
the markers. With the GTG Zeo and GTG Blas STAR 7/67/7 construct
approximately 2 times more colonies were formed. Also, the average
EpCAM expression levels of either 24 control versus STAR 7/67/7
colonies ranged from 2.44 pg/cell/day in the control to 6.51
pg/cell/day in the STAR7/67/7 construct (FIG. 21). This is a factor
2.7 increase. Also the average EpCAM production in the highest five
colonies was compared. In the control GTG this was 5.7 pg/cell/day,
versus 13.0 pg/cell/day with the GTG STAR 7/67/7 construct, an
increase of a factor 2.3. Also note that the average EpCAM
production mediated by the GTG start codon for the selection
markers was significantly higher than with the ATGmut/space start
codon.
[0263] FIG. 22 shows that with the TTG Zeo and TTG Blas control
construct no colonies were formed, similar as in example 9. With
the STAR 7/67/7 TTG construct colonies were formed. The average
EpCAM expression levels of the STAR 7/67/7 TTG colonies was 10.4
pg/cell/day (FIG. 22). This is again higher than with the
ATGmut/space and GTG as start codon (see FIGS. 20, 21 for
comparison). The average EpCAM production in the highest five TTG
STAR 7/67/7 colonies was 22.5 pg/cell/day.
[0264] The results show that the selection system can also be
applied to two simultaneously produced polypeptides, in this case
two polypeptides of a multimeric protein, casu quo an antibody. The
EpCAM production closely follows the results obtained with d2EGFP.
The TTG as start codon is more stringent than the GTG start codon,
which in turn is more stringent than the ATGmut/space (FIGS. 12 and
13). Higher stringency results in a decreasing number of colonies,
with no colonies in the case of the TTG control that has no STAR
elements, and higher stringency of the selection marker is coupled
to higher expression of the protein of interest.
Example 14
Creation and Testing of Additional GTG Zeocin-d2EGFP Bicistronic
Constructs with Differential Translation Efficiencies
[0265] Different versions of the Zeocin resistance gene with
mutated startcodons were described in Example 8. Besides the
described GTG codons (Example 8, FIG. 33A), additional modified
startcodons with distinct translational efficiency are possible.
These different Zeocin resistance gene versions were created (FIG.
33) and cloned upstream of the modified d2EGFP gene, as in Example
9.
Materials and Methods
Creation of Plasmids
[0266] Four Additional GTG Constructs were Made:
[0267] 1) GTG as a start codon in the Zeo resistance gene (FIG.
33A), but followed by a spacer sequence (FIG. 33B). The
mutspace-Zeo open reading frame was amplified with primer pair
GTGspaceBamHIF (SEQ. ID. NO. 122):
GAATTCGGATCCACCGTGGCGATCCAAAGACTGCCAAATCTAG and (wherein the
sequence following the underlined sequence comprises the spacer
sequence), and ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was
cut with EcoRI-BamHI, and ligated into pd2EGFP, cut with
EcoRI-BamHI, creating pZEO-GTGspace-d2EGFP.
[0268] 2) GTG as a start codon in the Zeo resistance gene, but in a
bad context (TTTGTG) (FIG. 33C). The Zeo open reading frame was
amplified with primer pair ZEOTTTGTGBamHIF (SEQ. ID. NO. 123):
GAATTCGGATCCTTTGTGGCCAAGTTGACCAGTGCCGTTCCG and ZEOWTreverse (SEQ.
ID. NO. 85), the PCR product was cut with EcoRI-BamHI, and ligated
into pd2EGFP, cut with EcoRI-BamHI, creating
pZEO(leu)-TTTGTG-d2EGFP.
[0269] 3) GTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 33A), but with an additional mutation in the Zeo open
reading frame at Pro9, which was replaced with threonine (Thr)
(FIG. 33D). The Thr9 mutation was introduced by amplifying the Zeo
open reading with primer pair ZEOForwardGTG-Thr9 (SEQ. ID. NO.
124): AATTGGATCCACCGTGGCCAAGTTGACCAGTGCCGTTACCGTGCTC and
ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was cut with
EcoRI-BamHI, and ligated into pd2EGFP, cut with EcoRI-BamHI,
creating pZEO-GTG-Thr9-d2EGFP.
[0270] 4) GTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 33A), but with an additional mutation in the Zeo open
reading frame at Pro9, with was replaced with Phenylalanine (Phe)
(FIG. 33E). The Phe9 mutation was introduced by amplifying the Zeo
open reading with primer pair ZEOForward GTG-Phe9 (SEQ. ID. NO.
125): AATTGGATCCACCGTGGCCAAGTTGACCAGTGCCGTTTTCGTGCTC and
ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was cut with
EcoRI-BamHI, and ligated into pd2EGFP, cut with EcoRI-BamHI,
creating pZEO-GTG-Phe9-d2EGFP.
Transfection, Culturing and Analysis of CHO Cells
[0271] Transfection, culturing and analysis of CHO-K1 cells was
performed as in Example 8.
Results
[0272] CHO-K1 cells were transfected with constructs that contain
the GTG Zeo (FIG. 33A), GTGspace Zeo (FIG. 33B), TTT GTG Zeo (also
called: GTGmut Zeo) (FIG. 33C), GTG Thr9 Zeo(leu) (FIG. 33D) and
GTG Phe9 Zeo(leu) (FIG. 33D) genes as selection gene, all being
cloned upstream of the d2EGFP reporter gene. These five constructs
were without STAR elements (Control) or with STAR elements 7 and 67
upstream of the CMV promoter and STAR 7 downstream from the d2EGFP
gene (FIG. 33). FIG. 34 shows that of the control constructs
without STAR elements only the GTG Zeo construct without STAR
elements gave colonies that expressed d2EGFP protein. In contrast,
all constructs containing STAR elements gave colonies that
expressed d2EGFP protein. The mean d2EGFP fluorescence signal of 11
GTG Zeo Control colonies was 20.3, of 13 GTG Zeo colonies with
STARs 7/67/7 104.9, of 24 GTG space Zeo 7/67/7 colonies 201.5, of 6
TTT GTG Zeo 7/67/7 colonies 310.5, of 22 GTG Thr9 Zeo 7/67/7
colonies 423, and of 16 GTG Phe9 Zeo colonies 550.2 (FIG. 34).
[0273] The higher stringencies of the novel GTG mutations correlate
with higher mean fluorescence signals (FIG. 34). The TTT GTG Zeo
7/67/7, however, gave only two high expressing colonies and a few
low expressing colonies. This may indicate that this mutation is at
the brink of the stringency that these cells can bear with a fixed
concentration of Zeocin added to the culture medium.
[0274] The Thr9 and Phe9 mutations do not influence the translation
efficiency of the Zeo mutants. Instead they reduce the
functionality of the Zeocin resistance protein, by preventing an
optimal interaction between the two halves of the Zeocin resistance
protein (Dumas et al, 1994). This implies that more of the protein
has to be produced to achieve resistance against the Zeocin in the
culture medium. As a consequence, the entire cassette has to be
transcribed at a higher level, eventually resulting in a higher
d2EGFP expression level.
[0275] It is concluded that the use of the described translation
efficiencies of the Zeocin resistance mRNA result in higher
expression levels of the d2EGFP protein, this in combination with
STAR elements.
[0276] This example further demonstrates the possibility to provide
for fine-tuning of the stringency of the selection system of the
invention, to achieve optimal expression levels of a protein of
interest. Clearly, the person skilled in the art will be capable of
combining these and other possibilities within the concepts
disclosed herein (e.g. mutate the zeocin at position 9 to other
amino acids, or mutate it in other positions; use a GTG or other
startcodon in a non-optimal translation initition context for
zeocin or other selection markers; or mutate other selection
markers to reduce their functionality, for instance use a sequence
coding for a neomycin resistance gene having a mutation at amino
acid residue 182 or 261 or both, see e.g. WO 01/32901), and the
like, to provide for such fine-tuning, and by simply testing
determine a suitable combination of features for the selection
marker, leading to enhanced expression of the polypeptide of
interest.
Example 15
Creation and Testing of Additional TTG Zeocin-d2EGFP Bicistronic
Constructs with Differential Translation Efficiencies
[0277] Different versions of the Zeocin resistance gene with
mutated startcodons were described in Example 8. Besides the
described TTG codons (FIG. 35A) additional modified startcodons
with distinct translational efficiency are possible. These
different Zeocin resistance gene versions were created and cloned
upstream of the modified d2EGFP gene (FIG. 35).
Materials and Methods
Creation of Plasmids
[0278] Three Additional TTG Constructs were Made:
[0279] 1) TTG as a start codon in the Zeo resistance gene (FIG.
35A), but followed by a spacer sequence (FIG. 35B). The Zeo open
reading frame (with the spacer sequence) was amplified with primer
pair TTGspaceBamHIF (SEQ. ID. NO. 126):
GAATTCGGATCCACCTTGGCGATCCAAAGACTGCCAAATCTAG and ZEOWTreverse(SEQ.
ID. NO. 85), the PCR product was cut with EcoRI-BamHI, and ligated
into pd2EGFP, cut with EcoRI-BamHI, creating
pZEO-TTGspace-d2EGFP.
[0280] 2) TTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 35A), but with an additional mutation in the Zeo open
reading frame at Pro9, with was replaced with threonine (Thr) (FIG.
35C). The Thr9 mutation was introduced by amplifying the Zeo open
reading with primer pair ZEOForwardTTG-Thr9 (SEQ. ID. NO. 127):
AATTGGATCCACCTTGGCCAAGTTGACCAGTGCCGTTACCGTGCTC and ZEOWTreverse
(SEQ. ID. NO. 85), the PCR product was cut with EcoRI-BamHI, and
ligated into pd2EGFP, cut with EcoRI-BamHI, creating
pZEO-TTG-Thr9-d2EGFP.
[0281] 3) TTG as a start codon in the Zeo resistance gene, instead
of ATG (FIG. 35A), but with an additional mutation in the Zeo open
reading frame at Pro9, with was replaced with Phenylalanine (Phe)
(FIG. 35D). The Phe9 mutation was introduced by amplifying the Zeo
open reading with primer pair ZEOForwardTTG-Phe9 (SEQ. ID. NO.
128): AATTGGATCCACCTTGGCCAAGTTGACCAGTGCCGTTTTCGTGCTC and
ZEOWTreverse (SEQ. ID. NO. 85), the PCR product was cut with
EcoRI-BamHI, and ligated into pd2EGFP, cut with EcoRI-BamHI,
creating pZEO-TTG-Phe9-d2EGFP.
Results
[0282] CHO-K1 cells were transfected with constructs that contain
the TTG Zeo (FIG. 35A), TTGspace Zeo (FIG. 35B), TTG Thr9 Zeo (FIG.
35C) and TTG Phe9 Zeo (FIG. 35D) genes as selection gene, all being
cloned upstream of the d2EGFP reporter gene. These four constructs
were without STAR elements (Control) or with STAR elements 7 and 67
upstream of the CMV promoter and STAR 7 downstream from the d2EGFP
gene (FIG. 35). FIG. 36 shows that of the control constructs
without STAR elements only the TTG Zeo construct without STAR
elements gave colonies that expressed d2EGFP protein. In contrast,
all constructs containing STAR elements gave colonies that
expressed d2EGFP protein. The mean d2EGFP fluorescence signal of 3
TTG Zeo Control colonies was 26.8, of 24 TTG Zeo colonies with
STARs 7/67/7 426.8, of 24 TTGspace Zeo 7/67/7 colonies 595.7, of 2
TTG Thr9 Zeo 7/67/7 colonies 712.1, and of 3 TTG Phe9 Zeo colonies
677.1(FIG. 36).
[0283] The higher stringencies of the novel TTG mutations correlate
with higher mean fluorescence signals (FIG. 36). The TTG Thr9 Zeo
7/67/7 and TTG Phe9 Zeo 7/67/7 constructs, however, gave only two
high expressing colonies each and a few low expressing colonies.
This may indicate that these mutations are at the brink of the
stringency that the cells can bear with a fixed concentration of
Zeocin added to the culture medium.
[0284] It is concluded that the use of the described translation
efficiencies of the Zeocin resistance mRNA result in higher
expression levels of the d2EGFP protein, this in combination with
STAR elements.
Example 16
Creation and Testing of Puromycin-d2EGFP Bicistronic Constructs
with Differential Translation Efficiencies
[0285] There are three internal ATGs in the puromycin resistance
gene, each of which codes for a methionine (FIG. 28, FIG. 37A).
These ATGs have to be eliminated (FIG. 37B,C), since they will
serve as start codon when the ATG startcodon (or the context
thereof) has been modified, and this will result in peptides that
do not resemble puromycin resistance protein. More importantly,
these ATGs will prevent efficient translation of the gene of
interest, as represented by d2EGFP in this example for purposes of
illustration. The methionines were changed into leucine, like in
the zeocin resistance protein (example 8). However, instead of
using the TTG codon for leucine (for instance in Zeocin in example
8), now the CTG codon for leucine was chosen (in humans, for
leucine the CTG codon is used more often than the TTG codon). To
eliminate the internal ATGs, the puromycin resistance protein open
reading frame was first amplified with 4 primer pairs, generating 4
puromycin resistance protein fragments. The primer pairs were:
TABLE-US-00002 PURO BamHI F (SEQ. ID. NO. 129):
GATCGGATCCATGGTTACCGAGTACAAGCCCACGGT, PURO300 R LEU (SEQ. ID. NO.
130): CAGCCGGGAACCGCTCAACTCGGCCAGGCGCGGGC; and PURO300FLEU (SEQ.
ID. NO. 131): CGAGTTGAGCGGTTCCCGGCTGGCCGCGCAGCAACAGCTGGAAGGCCTC,
PURO600RLEU (SEQ. ID. NO. 132):
AAGCTTGAATTCAGGCACCGGGCTTGCGGGTCAGGCACCAGGTC.
This generates two PCR products, corresponding to the 5' and 3'
part of the puromycin resistance gene. The two products were added
together and amplified with PURO BamHI F (SEQ. ID.
NO.129)--PURO600RLEU (SEQ. ID. NO. 132). The resulting PCR product
was cut with BamHI-EcoRI and ligated, creating pCMV-ATGPURO (leu).
Sequencing of this clone verified that all three internal ATGs had
been converted. The entire puromycin open reading frame was then
amplified with PUROBamHI TTGIF (SEQ. ID. NO. 133):
GAATTCGGATCCACCTTGGTTACCGAGTACAAGCCCACGGTG and PURO600RLEU (SEQ.
ID. NO.132). This primer introduces an extra codon (GTT) directly
after the TTG startcodon, because the `G` at nucleotide +4 is
introduced for an optimal context, and hence two more nucleotides
are introduced to preserve the reading frame. Results
[0286] CHO-K1 cells were transfected with the construct that
contains the TTG Puro (FIG. 38) gene as selection gene, cloned
upstream of the d2EGFP reporter gene. Selection was under 10
.mu.g/ml puromycin. The construct was without STAR elements
(Control) or with STAR elements 7 and 67 upstream of the CMV
promoter and STAR 7 downstream from the d2EGFP gene (FIG. 38). FIG.
38 shows that the average d2EGFP fluorescence signal of 24 TTG Puro
Control colonies was 37.9, of 24 TTG Puro colonies with STARs
7/67/7 75.5. Moreover, when the average of the five highest values
is taken, the d2EGFP fluorescence signal of TTG Puro Control
colonies was 69.5, and of TTG Puro colonies with STARs 7/67/7
186.1, an almost three-fold increase in d2EGFP fluorescence signal.
This shows that the described, modified translation efficiency of
the Puromycin resistance mRNA result in higher expression levels of
the d2EGFP protein, this in combination with STAR elements.
[0287] This experiment demonstrates that the puromycin resistance
gene can be mutated to remove the ATG sequences therefrom, while
remaining functional. Moreover it is concluded that the selection
method of the invention also works with yet another selection
marker, puromycin.
Example 17
Creation and Testing of Neomycin Constructs with Differential
Translation Efficiencies
[0288] There are sixteen internal ATGs in the neomycin resistance
gene, five of which code for a methionine in the neomycin open
reading frame (FIG. 31, FIG. 39A). All these sixteen ATGs have to
be eliminated (FIG. 39B,C), since they will serve as start codon
when the ATG startcodon (or the context thereof) has been modified,
and this will result in peptides that do not resemble neomycin
resistance protein, and this will decrease the translation from the
downstream open reading frame coding for the polypeptide of
interest in the transcription units of the invention. To eliminate
the internal ATGs, the neomycin resistance protein open reading
frame was entirely synthesized by a commercial provider (GeneArt,
Germany), wherein all internal coding ATGs (for Met) where replaced
by CTGs (coding for Leu), and non-coding ATGs were replaced such
that a degenerated codon was used and hence no mutations in the
protein sequence resulted; the synthesised sequence of the neomycin
is given in SEQ. ID. NO. 134. In order to replace the ATG start
codon with GTG (FIG. 39B) or TTG FIG. 39C), the synthesized
neomycin gene was amplified with primer pairs NEO-F-HindIII (SEQ.
ID. NO. 136): GATCAAGCTTTTGGATCGGCCATTGAAACAAGACGGATTG and NEO
EcoRI 800R (SEQ. ID. NO. 137):
AAGCTTGAATTCTCAGAAGAACTCGTCAAGAAGGCG.
Results
[0289] E. coli bacteria were used to test the functionality of the
neomycin resistance protein from which all ATGs were removed. E.
coli bacteria were transformed with the constructs that contain the
GTG Neo (FIG. 39B) or TTG Neo (FIG. 39C) gene as selection gene.
Selection took place by growing the bacteria on kanamycin. Only a
functional neomycin resistance gene can give resistance against
kanamycin. Transformation with either modified Neo gene resulted in
the formation of E. coli colonies, from which the plasmid
containing the gene could be isolated. This shows that the
described, modified translation efficiencies of the Neomycin
resistance mRNAs, as well as the removal of all ATGs from the Neo
open reading frame result in the production of functional neomycin
resistance protein.
[0290] The mutated neomycin resistance genes are incorporated in a
multicistronic transcription unit of the invention, and used for
selection with G418 or neomycin in eukaryotic host cells.
Example 18
Creation and Testing of dhfr Constructs with Differential
Translation Efficiencies
[0291] There are eight internal ATGs in the dhfr gene, six of which
code for a methionine in the dhfr open reading frame (FIG. 29, FIG.
40A). All these ATGs have to be eliminated (FIGS. 40B,C), since
they will serve as start codon when the ATG startcodon (or the
context thereof) has been modified, and this will result in
peptides that do not resemble dhfr protein, and will decrease the
translation from the downstream open reading frame coding for the
polypeptide of interest in the transcription units of the
invention. To eliminate the internal ATGs, the dhfr protein open
reading frame was entirely synthesized (SEQ. ID. NO. 138), as
described above for neomycin. In order to replace the ATG start
codon with GTG (FIG. 40B) or TTG (FIG. 40C), the synthesized DHFR
gene was amplified with primers DHFR-F-HindIII (SEQ. ID. NO. 140):
GATCAAGCTTTTGTTCGACCATTGAACTGCATCGTC and DHFR-EcoRI-600-R (SEQ. ID.
NO. 141): AGCTTGAATTCTTAGTCTTTCTTCTCGTAGACTTC.
Results
[0292] E. coli bacteria were used to test the functionality of the
dhfr protein from which all ATGs were removed. E. coli was
transformed with the constructs that contain the GTG dhfr (FIG.
40B) or TTG dhfr (FIG. 40C) gene. Selection took place by growing
the bateria on trimethoprim (Sigma T7883-56). Only a functional
dhfr gene can give resistance against trimethoprim. Transformation
with either modified dhfr gene resulted in the formation of E. coli
colonies, from which the plasmid containing the gene could be
isolated. This shows that the described, modified translation
efficiencies of the dhfr mRNAs, as well as the removal of all ATGs
from the dhfr open reading frame result in the production of
functional dhfr protein.
[0293] The mutated dhfr genes are incorporated in a multicistronic
transcription unit of the invention, and used for selection with
methotrexate in eukaryotic host cells.
Example 20
Testing of Zeocin- and Blasticidin Constructs with Differential
Translation Efficiencies in PER.C6 Cells
[0294] Various Zeocin and blasticidin genes with mutated
startcodons, all cloned upstream of the d2EGFP gene were tested in
the PER.C6 cell line.
Results
[0295] The GTG Zeocin and GTGspace Zeocin resistance gene
modifications (see also Example 14; FIG. 41) and the GTG
blasticidin and TTG blasticidin resistance gene modifications (see
also Example 11; FIG. 42), all cloned upstream of the d2EGFP gene
were transfected to PER.C6 cells. As shown in FIG. 41, transfection
with both the GTG Zeocin and GTGspace Zeocin gene resulted in
colonies that expressed d2EGFP. The average d2EGFP fluorescence
signal of 20 GTG Zeo colonies was 63.8, while the average d2EGFP
signal of 20 GTGspace Zeo colonies was 185, demonstrating that also
in PER.C6 cells the GTGspace Zeo has a higher translation
stringency than the GTG Zeo mRNA.
[0296] As shown in FIG. 42, transfection with both the GTG
Blasticidin and TTG Blasticidin gene resulted in colonies that
expressed d2EGFP. The average d2EGFP fluorescence signal of 20 GTG
Blasticidin colonies was 71.4, while the average d2EGFP
fluorescence signal of 20 TTG Blasticidin colonies was 135,
demonstrating that also in PER.C6 cells the TTG Blasticidin has a
higher translation stringency than the GTG Blasticidin mRNA.
[0297] This example demonstrates that the selection system of the
invention can also be used in other cells than CHO cells.
Example 21
Testing of the Addition of a Transcriptional Pause Signal to a TTG
Zeocin-d2EGFP Construct
[0298] A TRAnscription Pause (TRAP) sequence is thought to, at
least in part, prevent formation of antisense RNA or, to at least
in part, prevent transcription to enter said protein expression
unit (see WO 2004/055215). A TRAP sequence is functionally defined
as a sequence which when placed into a transcription unit, results
in a reduced level of transcription in the nucleic acid present on
the 3' side of the TRAP when compared to the level of transcription
observed in the nucleic acid on the 5' side of the TRAP, and
non-limiting examples of TRAP sequences are transcription
termination signals. In order to function to prevent or decrease
transcription to enter the transcription unit, the TRAP is to be
placed upstream of a promoter driving expression of the
transcription unit and the TRAP should be in a 5' to 3' direction.
In order to prevent at least in part formation of antisense RNA,
the TRAP should be located downstream of the open reading frame in
a transcription unit and present in a 3' to 5' direction (that is,
in an opposite orientation as the normal orientation of a
transcriptional termination sequence that is usually present behind
the open reading frame in a transcription unit). A combination of a
TRAP upstream of the promoter in a 5' to 3' orientation and a TRAP
downstream of the open reading frame in a 3' to 5' oreintation is
preferred. Adding a TRAP sequence to a STAR element improves the
effects of STAR elements on transgene expression (see WO
2004/055215). Here we test the effects of the TRAP sequence in the
context of the TTG Zeo resistance gene.
Results
[0299] The TTG Zeocin-d2EGFP cassette that was flanked with STAR7
elements (FIG. 43) was modified by the addition of the SPA/pause
TRAP sequence (see WO 2004/055215); SEQ. ID. NO. 142), both
upstream of the 5' STAR7 (in 5' to 3' direction) and downstream of
the 3' STAR7 (in 3' to 5' direction) (FIG. 43). Both STAR 7/7 and
TRAP-STAR 7/7-TRAP containing vectors were transfected to CHO-K1.
Stable colonies were isolated and the d2EGFP fluorescence
intensities were measured. As shown in FIG. 43 the average d2EGFP
fluorescence signal of 23 TTG Zeo STAR 7/7 colonies was 455.1,
while the average d2EGFP fluorescence signal of 23 TTG Zeo
TRAP-STAR 7/7-TRAP colonies was 642.3. The average d2EGFP
fluorescence signal in highest 5 TTG Zeo STAR 7/7 colonies was
705.1, while the average d2EGFP fluorescence signal of 5 TTG Zeo
TRAP-STAR 7/7-TRAP colonies was 784.7.
[0300] This result indicates that the addition of TRAPs does not
enhance the d2EGFP fluorescence signal in the highest colonies, but
that there is a significant raise in the number of high expressing
colonies. Whereas only 5 TTG Zeo STAR 7/7 colonies had d2EGFP
signal above 600, 17 TTG Zeo TRAP-STAR 7/7-TRAP colonies had a
d2EGFP fluorescence signal above 600.
[0301] In the experiment 3 .mu.g DNA of each plasmid was
transfected. However, whereas the transfection efficiency was
similar, the total number of colonies with the TTG Zeo STAR 7/7
plasmid was 62, while the total number of colonies with the TTG Zeo
TRAP-STAR 7/7-TRAP plasmid was 116, almost a doubling.
[0302] We conclude that addition of TRAP elements to the STAR
containing plasmids with modified Zeocin resistance gene
translation codons results in a significantly higher overall number
of colonies and that more colonies are present with the highest
expression levels.
Example 22
Copy-Number Dependency of Expression
[0303] We analyzed the EpCAM antibody expression levels in relation
to the number of integrated EpCAM DNA copies.
Results
[0304] The construct that was tested was TTG-Zeo-Light Chain
(LC)-TTG-Blas-Heavy Chain (HC), both expression units being under
the control of the CMV promoter (see FIG. 44). This construct
contained STAR 7 and 67 (see FIG. 44). Selection conditions were
such that with 200 .mu.g/ml Zeocin and 20 .mu.g/ml Blasticidin in
the culture medium no control colonies (no STARs) survived and only
STAR 7/67/7 colonies survived.
[0305] DNA was isolated when colonies were 60 days under Zeocin and
Blasticidin selection pressure (see FIG. 44). The R.sup.2 value is
calculated and shown. In the entire range from 5 to 40 pg/cell/day
EpCAM there was a high degree of copy number dependency, as
signified by a relatively high R.sup.2 of 0.5978 (FIG. 44). The
data show that in the novel selection system, in colonies that
contain TTG Zeo-TTG Blas EpCAM STAR 7/67/7 constructs there is copy
number dependent EpCAM expression.
Example 23
Methotrexate Induction of Higher EpCAM Expression
[0306] We analyzed EpCAM antibody expression levels after
incubation of clones with methotrexate (MTX). The purpose of this
experiment was to determine whether amplification of a
STAR-containing construct would result in higher EpCAM expression.
MTX acts through inhibition of the dhfr gene product. While some
CHO strains that are dhfr-deficient have been described, CHO-K1 is
dhfr.sup.+. Therefore relatively high concentrations of MTX in the
culture medium have to be present to select for amplification by
increased MTX concentrations in CHO-K1 cells.
Results
[0307] The construct that was tested was TTG-Zeo-Heavy Chain
(HC)-TTG-Blas-Light Chain (LC), both expression units being under
the control of the CMV promoter. Upstream of each CMV promoter
STAR67 was positioned and STAR7 was used to flank the entire
cassette (see also Example 13, FIG. 22 for such a construct). This
construct was further modified by placing an SV40-dhfr cassette (a
mouse dhfr gene under control of an SV40 promoter) between the HC
and LC cassettes, upstream of the second STAR67 (FIG. 45). CHO-K1
cells were transfected. Selection was done with 100 .mu.g/ml Zeocin
and 10 .mu.g/ml Blasticidin in the culture medium. No control
colonies (without STAR elements) survived and only colonies with
constructs containing the STAR elements survived. Colonies were
isolated and propagated before measuring EpCAM expression levels.
Six colonies that produced between 20 and 35 pg/cell/day were
transferred to medium containing 100 nM MTX. This concentration was
raised to 500 nM, 1000 nM and finally to 2000 nM with two weeks
periods in between each step. After two weeks on 2000 nM MTX, EpCAM
concentrations were measured. As shown in FIG. 45, four colonies
showed enhanced EpCAM production. Colony 13: from 22 to 30; colony
14: from 28 to 42; colony 17: from 20 to 67 and colony 19: from 37
to 67 pg/cell/day. Colonies 4 and 16 showed no enhanced EpCAM
expression. We conclude that addition of methotrexate to the
culture medium of CHO-K1 colonies created with the selection system
of the invention can result in enhanced protein expression. Hence,
STAR elements and the selection method of the invention can be
combined with and are compatible with MTX-induced enhancement of
protein expression levels.
Example 24
TTG-Zeo Selection Operates in the Context of Different
Promoters
[0308] We analyzed d2EGFP expression levels in the context of the
TTG Zeo selection marker and different promoters. We compared the
action of STAR elements in the context of the CMV
enhancer/promoter, the SV40 enhancer/promoter and the CMV
enhancer/.beta.-actin promoter.
Results
[0309] In FIG. 46 we indicate the promoters we tested in the
context of the TTG Zeo selection marker. The tested plasmids
consisted of the indicated control constructs with three different
promoters and STAR constructs which were flanked with STAR 7 and
STAR 67 at the 5' end and STAR 7 at the 3' end. The constructs were
transfected to CHO-K1 cell and selection was performed with 200
.mu.g/ml Zeocin in the culture medium. Up to 23 independent
colonies were isolated and propagated before analysis of d2EGFP
expression levels. As shown in FIG. 46, incorporation of STAR
elements in constructs with the CMV enhancer/promoter, the SV40
enhancer/promoter or the CMV enhancer/.beta.-actin promoter all
resulted in the formation of colonies with higher d2EGFP expression
levels than with the corresponding control constructs. This shows
that the selection system of the invention, in combination with
STAR elements, operates well in the context of different promoters.
Further analysis showed that the mean of CMV-driven d2EGFP values
was significantly higher than the mean of SV40-driven d2EGFP values
(p<0.05). In contrast, the mean of CMV-driven d2EGFP values did
not significantly differ from CMV/.beta. actin-driven d2EGFP values
(p=0.2).
Example 25
Comparison of Different STAR Elements in the TTG-Zeo Selection
System
[0310] We analyzed d2EGFP expression levels in the context of the
CMV promoter-TTG Zeo selection marker and 53 different STAR
elements, to obtain more insight in which STAR elements give the
best results in this context.
Results
[0311] We cloned 53 STAR elements up-and downstream of the CMV
promoter-TTG Zeo-d2EGFP cassette. The following STAR elements were
tested in such constructs: STAR2-12, 14, 15, 17-20, 26-34, 36, 37,
39, 40, 42-49, 51, 52, 54, 55, 57-62, 64, 65, 67. The constructs
were transfected to CHO-K1 cells and selection was performed with
200 .mu.g/ml Zeocin in the culture medium. Up to 24 independent
colonies were isolated and propagated before analysis of d2EGFP
expression levels. Incorporation of STAR elements in the constructs
resulted in different degrees of enhanced d2EGFP expression, as
compared to the control. Incorporation of STAR elements 14, 18 and
55 in this experiment did not result in an increase of average
d2EGFP expression over the control (no STAR element). Although some
constructs (with STAR elements 2, 3, 10, 42, 48 and 49) in this
experiment gave rise to only a few colonies, all tested STAR
elements except 14, 18 and 55 resulted in average d2EGFP expression
levels higher than for the control. It should be noted that some
STAR elements may act in a more cell type specific manner and that
it is well possible that STAR 14, 18 and 55 work better in other
cell types, with other promoters, other selection markers, or in
different context or configuration than in the particular set of
conditions tested here. Addition of 10 STAR elements, namely STAR
elements 7, 9, 17, 27, 29, 43, 44, 45, 47 and 61, induced average
d2EGFP expression levels higher than 5 times the average d2EGFP
expression level of the control. We retransformed the control and 7
constructs with STAR elements and repeated the experiment. The
results are shown in FIG. 47. Incorporation of STAR elements in the
constructs resulted in different degrees of enhanced d2EGFP
expression, as compared to the control (FIG. 47). The average
d2EGFP expression level in colonies transfected with the control
construct was 29. The averages from d2EGFP expression levels in
colonies with the 7 different STAR constructs ranged between 151
(STAR 67) and 297 (STAR 29). This is a factor of 5 to 10-fold
higher than the average in the control colonies.
[0312] We conclude that a) the vast majority of STAR elements have
a positive effect on gene expression levels, b) there is variation
in the degree of positive effects induced by the different STAR
elements, and c) 10 out of 53 tested STAR elements induce more than
5-fold average d2EGFP expression levels, as compared to the
control, and that STAR elements can induce a 10-fold higher average
d2EGFP expression level, as compared to the control.
Example 26
Other Chromatin Control Elements in the Context of a Selection
System of the Invention
[0313] DNA elements such as the HS4 hypersensitive site in the
locus control region of the chicken .beta.-globin locus (Chung et
al, 1997), matrix attachment regions (MAR) (Stief et al, 1989) and
a ubiquitous chromatin opening element (UCOE) (Williams et al,
2005) have been reported to have beneficial effects on gene
expression when these DNA elements are incorporated in a vector. We
combined these DNA elements with the selection system of the
invention.
Results
[0314] The 1.25 kb HS4 element was cloned into the cassette
encompassing the CMV promoter, TTG Zeo and d2EGFP by a three way
ligation step to obtain a construct with a tandem of 2 HS4 elements
(Chung et al, 1997). This step was done both for the 5' and 3' of
the cassette encompassing the CMV promoter, TTG Zeo and d2EGFP. The
2959 bp long chicken lysozyme MAR (Stief et al, 1989) was cloned 5'
and 3' of the cassette encompassing the CMV promoter, TTG Zeo and
d2EGFP. The 2614 bp long UCOE (Williams et al, 2005) was a
NotI-KpnI fragment, excised from a human BAC clone (RP11-93D5),
corresponding to nucleotide 29449 to 32063. This fragment was
cloned 5' of the CMV promoter. The STAR construct contained STAR7
and STAR67 5' of the CMV promoter and STAR7 3' of the cassette.
These four constructs, as well as the control construct without
flanking chromatin control DNA elements, were transfected to CHO-K1
cells. Selection was performed by 200 .mu.g/ml Zeocin in the
culture medium. Colonies were isolated, propagated and d2EGFP
expression levels were measured. As shown in FIG. 48 constructs
with all DNA elements resulted in the formation of d2EGFP
expressing colonies. However, incorporation of 2.times.HS4 elements
and the UCOE did not result in the formation of colonies that
displayed higher d2EGFP expression levels, in comparison with the
control colonies. In contrast, incorporation of the lysozyme MAR
resulted in the formation of colonies that expressed d2EGFP
significantly higher. The mean expression level induced by MAR
containing constructs was four-fold higher than in the control
colonies. Best results were obtained, however, by incorporating
STAR 7 and 67 in the construct. An almost ten-fold increase in the
mean d2EGFP expression level was observed, as compared to the
control colonies. We conclude that other chromatin control DNA
elements such as MARs can be used in the context of the selection
system of the invention. However, the best results were obtained
when STAR elements were used as chromatin control elements.
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Sequence CWU 1
1
142 1 749 DNA Homo sapiens misc_feature sequence of STAR1 1
atgcggtggg ggcgcgccag agactcgtgg gatccttggc ttggatgttt ggatctttct
60 gagttgcctg tgccgcgaaa gacaggtaca tttctgatta ggcctgtgaa
gcctcctgga 120 ggaccatctc attaagacga tggtattgga gggagagtca
cagaaagaac tgtggcccct 180 ccctcactgc aaaacggaag tgattttatt
ttaatgggag ttggaatatg tgagggctgc 240 aggaaccagt ctccctcctt
cttggttgga aaagctgggg ctggcctcag agacaggttt 300 tttggccccg
ctgggctggg cagtctagtc gaccctttgt agactgtgca cacccctaga 360
agagcaacta cccctataca ccaggctggc tcaagtgaaa ggggctctgg gctccagtct
420 ggaaaatctg gtgtcctggg gacctctggt cttgcttctc tcctcccctg
cactggctct 480 gggtgcttat ctctgcagaa gcttctcgct agcaaaccca
cattcagcgc cctgtagctg 540 aacacagcac aaaaagccct agagatcaaa
agcattagta tgggcagttg agcgggaggt 600 gaatatttaa cgcttttgtt
catcaataac tcgttggctt tgacctgtct gaacaagtcg 660 agcaataagg
tgaaatgcag gtcacagcgt ctaacaaata tgaaaatgtg tatattcacc 720
ccggtctcca gccggcgcgc caggctccc 749 2 883 DNA Homo sapiens
misc_feature sequence of STAR2 2 gggtgcttcc tgaattcttc cctgagaagg
atggtggccg gtaaggtccg tgtaggtggg 60 gtgcggctcc ccaggccccg
gcccgtggtg gtggccgctg cccagcggcc cggcaccccc 120 atagtccatg
gcgcccgagg cagcgtgggg gaggtgagtt agaccaaaga gggctggccc 180
ggagttgctc atgggctcca catagctgcc ccccacgaag acggggcttc cctgtatgtg
240 tggggtccca tagctgccgt tgccctgcag gccatgagcg tgcgggtcat
agtcgggggt 300 gccccctgcg cccgcccctg ccgccgtgta gcgcttctgt
gggggtggcg ggggtgcgca 360 gctgggcagg gacgcagggt aggaggcggg
gggcagcccg taggtaccct gggggggctt 420 ggagaagggc gggggcgact
ggggctcata cgggacgctg ttgaccagcg aatgcataga 480 gttcagatag
ccaccggctc cggggggcac ggggctgcga cttggagact ggccccccga 540
tgacgttagc atgcccttgc ccttctgatc ctttttgtac ttcatgcggc gattctggaa
600 ccagatcttg atctggcgct cagtgaggtt cagcagattg gccatctcca
cccggcgcgg 660 ccggcacagg tagcggttga agtggaactc tttctccagc
tccaccagct gcgcgctcgt 720 gtaggccgtg cgcgcgcgct tggacgaagc
ctgccccggc gggctcttgt cgccagcgca 780 gctttcgcct gcgaggacag
agagaggaag agcggcgtca ggggctgccg cggccccgcc 840 cagcccctga
cccagcccgg cccctccttc caccaggccc caa 883 3 2126 DNA Homo sapiens
misc_feature sequence of STAR3 3 atctcgagta ctgaaatagg agtaaatctg
aagagcaaat aagatgagcc agaaaaccat 60 gaaaagaaca gggactacca
gttgattcca caaggacatt cccaaggtga gaaggccata 120 tacctccact
acctgaacca attctctgta tgcagattta gcaaggttat aaggtagcaa 180
aagattagac ccaagaaaat agagaacttc caatccagta aaaatcatag caaatttatt
240 gatgataaca attgtctcca aaggaacaag gcagagtcgt gctagcagag
gaagcacgtg 300 agctgaaaac agccaaatct gctttgtttt catgacacag
gagcataaag tacacaccac 360 caactgacct attaaggctg tggtaaaccg
attcatagag agaggttcta aatacattgg 420 tccctcacag gcaaactgca
gttcgctccg aacgtagtcc ctggaaattt gatgtccagt 480 atagaaaagc
agagcagtca aaaaatatag ataaagctga accagatgtt gcctgggcaa 540
tgttagcagc accacactta agatataacc tcaggctgtg gactccctcc ctggggagcg
600 gtgctgccgg cggcgggcgg gctccgcaac tccccggctc tctcgcccgc
cctcccgttc 660 tcctcgggcg gcggcggggg ccgggactgc gccgctcaca
gcggcggctc ttctgcgccc 720 ggcctcggag gcagtggcgg tggcggccat
ggcctcctgc gttcgccgat gtcagcattt 780 cgaactgagg gtcatctcct
tgggactggt tagacagtgg gtgcagccca cggagggcga 840 gttgaagcag
ggtggggtgt cacctccccc aggaagtcca gtgggtcagg gaactccctc 900
ccctagccaa gggaggccgt gagggactgt gcccggtgag agactgtgcc ctgaggaaag
960 gtgcactctg gcccagatac tacacttttc ccacggtctt caaaacccgc
agaccaggag 1020 attccctcgg gttcctacac caccaggacc ctgggtttca
accacaaaac cgggccattt 1080 gggcagacac ccagctagct gcaagagttg
tttttttttt tatactcctg tggcacctgg 1140 aacgccagcg agagagcacc
tttcactccc ctggaaaggg ggctgaaggc agggaccttt 1200 agctgcgggc
tagggggttt ggggttgagt gggggagggg agagggaaaa ggcctcgtca 1260
ttggcgtcgt ctgcagccaa taaggctacg ctcctctgct gcgagtagac ccaatccttt
1320 cctagaggtg gagggggcgg gtaggtggaa gtagaggtgg cgcggtatct
aggagagaga 1380 aaaagggctg gaccaatagg tgcccggaag aggcggaccc
agcggtctgt tgattggtat 1440 tggcagtgga ccctcccccg gggtggtgcc
ggaggggggg atgatgggtc gaggggtgtg 1500 tttatgtgga agcgagatga
ccggcaggaa cctgccccaa tgggctgcag agtggttagt 1560 gagtgggtga
cagacagacc cgtaggccaa cgggtggcct taagtgtctt tggtctcctc 1620
caatggagca gcggcggggc gggaccgcga ctcgggttta atgagactcc attgggctgt
1680 aatcagtgtc atgtcggatt catgtcaacg acaacaacag ggggacacaa
aatggcggcg 1740 gcttagtcct acccctggcg gcggcggcag cggtggcgga
ggcgacggca ctcctccagg 1800 cggcagccgc agtttctcag gcagcggcag
cgcccccggc aggcgcggtg gcggtggcgc 1860 gcagccaggt ctgtcaccca
ccccgcgcgt tcccaggggg aggagactgg gcgggagggg 1920 ggaacagacg
gggggggatt caggggcttg cgacgcccct cccacaggcc tctgcgcgag 1980
ggtcaccgcg gggccgctcg gggtcaggct gcccctgagc gtgacggtag ggggcggggg
2040 aaaggggagg agggacaggc cccgcccctc ggcagggcct ctagggcaag
ggggcggggc 2100 tcgaggagcg gaggggggcg gggcgg 2126 4 1625 DNA Homo
sapiens misc_feature sequence of STAR4 4 gatctgagtc atgttttaag
gggaggattc ttttggctgc tgagttgaga ttaggttgag 60 ggtagtgaag
gtaaaggcag tgagaccacg taggggtcat tgcagtaatc caggctggag 120
atgatggtgg ttcagttgga atagcagtgc atgtgctgta acaacctcag ctgggaagca
180 gtatatgtgg cgttatgacc tcagctggaa cagcaatgca tgtggtggtg
taatgacccc 240 agctgggtag ggtgcatgtg gtgtaacgac ctcagctggg
tagcagtgtg tgtgatgtaa 300 caacctcagc tgggtagcag tgtacttgat
aaaatgttgg catactctag atttgttatg 360 agggtagtgc cattaaattt
ctccacaaat tggttgtcac gtatgagtga aaagaggaag 420 tgatggaaga
cttcagtgct tttggcctga ataaatagaa gacgtcattt ccagttaatg 480
gagacaggga agactaaagg tagggtggga ttcagtagag caggtgttca gttttgaata
540 tgatgaactc tgagagagga aaaacttttt ctacctctta gtttttgtga
ctggacttaa 600 gaattaaagt gacataagac agagtaacaa gacaaaaata
tgcgaggtta tttaatattt 660 ttacttgcag aggggaatct tcaaaagaaa
aatgaagacc caaagaagcc attagggtca 720 aaagctcata tgccttttta
agtagaaaat gataaatttt aacaatgtga gaagacaaag 780 gtgtttgagc
tgagggcaat aaattgtggg acagtgatta agaaatatat gggggaaatg 840
aaatgataag ttattttagt agatttattc ttcatatcta ttttggcttc aacttccagt
900 ctctagtgat aagaatgttc ttctcttcct ggtacagaga gagcaccttt
ctcatgggaa 960 attttatgac cttgctgtaa gtagaaaggg gaagatcgat
ctcctgtttc ccagcatcag 1020 gatgcaaaca tttccctcca ttccagttct
caaccccatg gctgggcctc atggcattcc 1080 agcatcgcta tgagtgcacc
tttcctgcag gctgcctcgg gtagctggtg cactgctagg 1140 tcagtctatg
tgaccaggag ctgggcctct gggcaatgcc agttggcagc ccccatccct 1200
ccactgctgg gggcctccta tccagaaggg cttggtgtgc agaacgatgg tgcaccatca
1260 tcattcccca cttgccatct ttcaggggac agccagctgc tttgggcgcg
gcaaaaaaca 1320 cccaactcac tcctcttcag gggcctctgg tctgatgcca
ccacaggaca tccttgagtg 1380 ctgggcagtc tgaggacagg gaaggagtga
tgaccacaaa acaggaatgg cagcagcagt 1440 gacaggagga agtcaaaggc
ttgtgtgtcc tggccctgct gagggctggc gagggccctg 1500 ggatggcgct
cagtgcctgg tcggctgcaa gaggccagcc ctctgcccat gaggggagct 1560
ggcagtgacc aagctgcact gccctggtgg tgcatttcct gccccactct ttccttctaa
1620 gatcc 1625 5 1571 DNA Homo sapiens misc_feature sequence of
STAR5 5 cacctgattt aaatgatctg tctggtgagc tcactgggtc tttactcgca
tgctgggtcc 60 acagctccac tgtcctgcag ggtccgtgag tgtgggcccc
ttatctattt catcatcata 120 accctgcgtg tcctcaactc ctggcacata
ttgggtggcc ccatccacac acggttgttg 180 agtgaatcca tgagatgaca
aaggctatga tgtagactat atcatgagcc agaaccaggc 240 tttcctacct
ccagacaatc aagggccttg atttgggatt gagggagaaa ggagtagaag 300
ccaggaagga gaagagattg aggtttacca agggtgcaaa gtcctggccc ctgactgtag
360 gctgaaaact atagaaatga tagaacaatt ttgcaatgaa atgcagaaga
ccctgcatca 420 actttaggtg ggacttcggg tatttttatg gccacagaac
atcctcccat ttacctgcat 480 ggcccagaca cagacttcaa aacagttgag
gccagcaggc tccaggtaag tggtaggatt 540 ccagaatgcc ctcagagtgt
tgtgggaggc agcaggcgat tttcctggac ttctgagttt 600 atgagaaccc
caaaccccaa ttggcattaa cattgaggtc tcaatgtatc atggcaggaa 660
gcttccgagt ggtgaaaagg aaagtgaaca tcaaagctcg gaagacaaga gggtggagtg
720 atggcaacca agagcaagac ccttccctct cctgtgatgg ggtggctcta
tgtgaagccc 780 ccaaactgga cacaggtctg gcagaatgag gaacccactg
agatttagcg ccaacatcca 840 gcataaaagg gagactgaca tagaatttga
gttagttaaa aataaggcac aatgcttttc 900 atgtattcct gagttttgtg
gactggtgtt caatttgcag cattcttagt tgattaaatc 960 tgagatgaag
aaagagtgtc caacactttc accttggaaa gctctggaaa agcaaaaggg 1020
agagacaatt agcttcatcc attaactcac ttagtcatta tgcattcatt catgtaacta
1080 ccaaacacgt actgagtgcc taacactcct gagacactga gaagtttctt
gggaatacaa 1140 agatgaataa aaaccacgcc aggcaggagt tggaggaagg
ttctggatgc caccacgctc 1200 tacctcctgg ctggacacca ggcaatgttg
gtaaccttct gcctccaatt tctgcaaata 1260 cataattaat aaacacaagg
ttatcttcta aacagttctt aaaatgagtc aactttgttt 1320 aaacttgttc
tttttagaga aaaatgtatt tttgaaagag ttggttagtg ctaggggaaa 1380
tgtctgggca cagctcagtc tggtgtgaga gcaggaagca gctctgtgtg tctggggtgg
1440 gtacgtatgt aggacctgtg ggagaccagg ttgggggaag gcccctcctc
atcaagggct 1500 cctttgcttt ggtttgcttt ggcgtgggag gtgctgtgcc
acaagggaat acgggaaata 1560 agatctctgc t 1571 6 1173 DNA Homo
sapiens misc_feature sequence of STAR6 6 tgacccacca cagacatccc
ctctggcctc ctgagtggtt tcttcagcac agcttccaga 60 gccaaattaa
acgttcactc tatgtctata gacaaaaagg gttttgacta aactctgtgt 120
tttagagagg gagttaaatg ctgttaactt tttaggggtg ggcgagaggg atgacaaata
180 acaacttgtc tgaatgtttt acatttctcc ccactgcctc aagaaggttc
acaacgaggt 240 catccatgat aaggagtaag acctcccagc cggactgtcc
ctcggccccc agaggacact 300 ccacagagat atgctaactg gacttggaga
ctggctcaca ctccagagaa aagcatggag 360 cacgagcgca cagagcaggg
ccaaggtccc agggacagaa tgtctaggag ggagattggg 420 gtgagggtaa
tctgatgcaa ttactgtggc agctcaacat tcaagggagg gggaagaaag 480
aaacagtccc tgtcaagtaa gttgtgcagc agagatggta agctccaaaa tttgaaactt
540 tggctgctgg aaagttttag ggggcagaga taagaagaca taagagactt
tgagggttta 600 ctacacacta gacgctctat gcatttattt atttattatc
tcttatttat tactttgtat 660 aactcttata ataatcttat gaaaacggaa
accctcatat acccatttta cagatgagaa 720 aagtgacaat tttgagagca
tagctaagaa tagctagtaa gtaaaggagc tgggacctaa 780 accaaaccct
atctcaccag agtacacact cttttttttt ttccagtgta atttttttta 840
atttttattt tactttaagt tctgggatac atgtgcagaa ggtatggttt gttacatagg
900 tatatgtgtg ccatagtgga ttgctgcacc tatcaacccg tcatctaggt
ttaagcccca 960 catgcattag ctatttgtcc tgatgctctc cctcccctcc
ccacaccaga caggccttgg 1020 tgtgtgatgt tcccctccct gtgtccatgt
gttctcactg ttcagctccc acttatgagt 1080 gagaacgtgt ggtatttggt
tttctgttcc tgtgttagtt tgctgaggat gatggcttcc 1140 agcttcatcc
atgtccctgc aaaggacacg atc 1173 7 2101 DNA Homo sapiens misc_feature
sequence of STAR7 7 aggtgggtgg atcacccgag gtcaggagtt caagaccagc
ctggccaaca tggtaaaacc 60 tcgtctctac taaaaaatac gaaaaattag
ctggttgtgg tggtgcgtgc ttgtaatccc 120 agctactcgg gaggctgagg
caggagaatc acttgaatct gggaggcaga ggttgcagtg 180 agctgagata
gtgccattgc actccagcct gggcaacaga cggagactct gtctccaaaa 240
aaaaaaaaaa aaatcttaga ggacaagaat ggctctctca aacttttgaa gaaagaataa
300 ataaattatg cagttctaga agaagtaatg gggatatagg tgcagctcat
gatgaggaag 360 acttagctta actttcataa tgcatctgtc tggcctaaga
cgtggtgagc tttttatgtc 420 tgaaaacatt ccaatataga atgataataa
taatcacttc tgacccccct tttttttcct 480 ctccctagac tgtgaagcag
aaaccccata tttttcttag ggaagtggct acgcactttg 540 tatttatatt
aacaactacc ttatcaggaa attcatattg ttgccctttt atggatgggg 600
aaactggaca agtgacagag caaaatccaa acacagctgg ggatttccct cttttagatg
660 atgattttaa aagaatgctg ccagagagat tcttgcagtg ttggaggaca
tatatgacct 720 ttaagatatt ttccagctca gagatgctat gaatgtatcc
tgagtgcatg gatggacctc 780 agttttgcag attctgtagc ttatacaatt
tggtggtttt ctttagaaga aaataacaca 840 tttataaata ttaaaatagg
cccaagacct tacaagggca ttcatacaaa tgagaggctc 900 tgaagtttga
gtttgttcac tttctagtta attatctcct gcctgtttgt cataaatgcg 960
tttagtaggg agctgctaat gacaggttcc tccaacagag tgtggaagaa ggagatgaca
1020 gctggcttcc cctctgggac agcctcagag ctagtgggga aactatgtta
gcagagtgat 1080 gcagtgacca agaaaatagc actaggagaa agctggtcca
tgagcagctg gtgagaaaag 1140 gggtggtaat catgtatgcc ctttcctgtt
ttatttttta ttgggtttcc ttttgcctct 1200 caattccttc tgacaataca
aaatgttggt tggaacatgg agcacctgga agtctggttc 1260 attttctctc
agtctcttga tgttctctcg ggttcactgc ctattgttct cagttctaca 1320
cttgagcaat ctcctcaata gctaaagctt ccacaatgca gattttgtga tgacaaattc
1380 agcatcaccc agcagaactt aggttttttt ctgtcctccg tttcctgacc
tttttcttct 1440 gagtgcttta tgtcacctcg tgaaccatcc tttccttagt
catctaccta gcagtcctga 1500 ttcttttgac ttgtctccct acaccacaat
aaatcactaa ttactatgga ttcaatccct 1560 aaaatttgca caaacttgca
aatagattac gggttgaaac ttagagattt caaacttgag 1620 aaaaaagttt
aaatcaagaa aaatgacctt taccttgaga gtagaggcaa tgtcatttcc 1680
aggaataatt ataataatat tgtgtttaat atttgtatgt aacatttgaa taccttcaat
1740 gttcttattt gtgttatttt aatctcttga tgttactaac tcatttggta
gggaagaaaa 1800 catgctaaaa taggcatgag tgtcttatta aatgtgacaa
gtgaatagat ggcagaaggt 1860 ggattcatat tcagttttcc atcaccctgg
aaatcatgcg gagatgattt ctgcttgcaa 1920 ataaaactaa cccaatgagg
ggaacagctg ttcttaggtg aaaacaaaac aaacacgcca 1980 aaaaccttta
ttctctttat tatgaatcaa atttttcctc tcagataatt gttttattta 2040
tttattttta ttattattgt tattatgtcc agtctcactc tgtcgcctaa gctggcatga
2100 t 2101 8 1821 DNA Homo sapiens misc_feature sequence of STAR8
8 gagatcacct cgaagagagt ctaacgtccg taggaacgct ctcgggttca caaggattga
60 ccgaacccca ggatacgtcg ctctccatct gaggcttgct ccaaatggcc
ctccactatt 120 ccaggcacgt gggtgtctcc cctaactctc cctgctctcc
tgagcccatg ctgcctatca 180 cccatcggtg caggtccttt ctgaagagct
cgggtggatt ctctccatcc cacttccttt 240 cccaagaaag aagccaccgt
tccaagacac ccaatgggac attccccttc cacctccttc 300 tccaaagttg
cccaggtgtt catcacaggt tagggagaga agcccccagg tttcagttac 360
aaggcatagg acgctggcat gaacacacac acacacacac acacacacac acacacacac
420 acacgactcg aagaggtagc cacaagggtc attaaacact tgacgactgt
tttccaaaaa 480 cgtggatgca gttcatccac gccaaagcca agggtgcaaa
gcaaacacgg aatggtggag 540 agattccaga ggctcaccaa accctctcag
gaatattttc ctgaccctgg gggcagaggt 600 tggaaacatt gaggacattt
cttgggacac acggagaagc tgaccgacca ggcattttcc 660 tttccactgc
aaatgaccta tggcgggggc atttcacttt cccctgcaaa tcacctatgg 720
cgaggtacct ccccaagccc ccacccccac ttccgcgaat cggcatggct cggcctctat
780 ccgggtgtca ctccaggtag gcttctcaac gctctcggct caaagaagga
caatcacagg 840 tccaagccca aagcccacac ctcttccttt tgttataccc
acagaagtta gagaaaacgc 900 cacactttga gacaaattaa gagtccttta
tttaagccgg cggccaaaga gatggctaac 960 gctcaaaatt ctctgggccc
cgaggaaggg gcttgactaa cttctatacc ttggtttagg 1020 aaggggaggg
gaactcaaat gcggtaattc tacagaagta aaaacatgca ggaatcaaaa 1080
gaagcaaatg gttatagaga gataaacagt tttaaaaggc aaatggttac aaaaggcaac
1140 ggtaccaggt gcggggctct aaatccttca tgacacttag atataggtgc
tatgctggac 1200 acgaactcaa ggctttatgt tgttatctct tcgagaaaaa
tcctgggaac ttcatgcact 1260 gtttgtgcca gtatcttatc agttgattgg
gctcccttga aatgctgagt atctgcttac 1320 acaggtcaac tccttgcgga
agggggttgg gtaaggagcc cttcgtgtct cgtaaattaa 1380 ggggtcgatt
ggagtttgtc cagcattccc agctacagag agccttattt acatgagaag 1440
caaggctagg tgattaaaga gaccaacagg gaagattcaa agtagcgact tagagtaaaa
1500 acaaggttag gcatttcact ttcccagaga acgcgcaaac attcaatggg
agagaggtcc 1560 cgagtcgtca aagtcccaga tgtggcgagc ccccgggagg
aaaaaccgtg tcttccttag 1620 gatgcccgga acaagagcta ggcttccgga
gctaggcagc catctatgtc cgtgagccgg 1680 cgggagggag accgccggga
ggcgaagtgg ggcggggcca tccttctttc tgctctgctg 1740 ctgccgggga
gctcctggct ggcgtccaag cggcaggagg ccgccgtcct gcagggcgcc 1800
gtagagtttg cggtgcagag t 1821 9 1929 DNA Homo sapiens misc_feature
sequence of STAR9 9 cacttcctgg gagtggagca gaggctctgc gtggagcatc
catgtgcagt actcttaggt 60 acggaaggga ttgggctaaa ccatggatgg
gagctgggaa gggaagggac caacttcagg 120 ccccactggg acactggagc
tgccaccctt tagagccctc ctaaccctac accagaggct 180 gagggggacc
tcagacatca cacacatgct ttcccatgtt ttcagaaatc tggaaacgta 240
gaacttcagg ggtgagagtg cctagatatt gaatacaagg ctagattggg cttctgtaat
300 atcccaaagg accctccagc tttttcacca gcacctaatg cccatcagat
accaaagaca 360 cagcttagga gaggttcacc ctgaagctga ggaggaggca
gccggattag agttgactga 420 gcaaggatga ctgccttctc cacctgacga
tttcagctgc tgcccttttc ttttcctggg 480 aatgcctgtc gccatggcct
tctgtgtcca caggagagtt tgacccagat actcatggac 540 caggcaaagg
tgctgttcct cccagcccag ggcccaccat gaagcatgcc tgggagcctg 600
gtaaggaccc agccactcct gggctgttga cattggcttc tcttgcccag cattgtagcc
660 acgccactgc attgtactgt gagataagtc aaggtgggct caccaggacc
tgcactaaat 720 tgtgaaattc agctccaaag aactttggaa attacccatg
catttaagca aaatgaatga 780 tacctgagca aaccctttca cattggcaca
agttacaatc ctgtctcatc ctcttgatta 840 caaattccat ccaggcaaga
gctgtatcac cctgaggtct ccccattcat gttttggtca 900 ataatattta
gtttcctttt gaaaatagat ttttgtgtta ctccattatg atgggcagag 960
gccagatgct tatattctat ttaaatgact atgtttttct atctgtaact gggtttgtgt
1020 tcaggtggta aatgcttttt ttttgcagtc agaagattcc tggaaggcga
ccagaaatta 1080 gctggccgct gtcagacctg aagttacttc taaagggcct
ttagaaatga attctttttt 1140 atgccttctc tgaattctga gaagtaggct
tgacttcccc taagtgtgga gttgggagtc 1200 aactcttctg aaaagaaagt
ttcagagcat tttccaaagc catggtcagc tgtgggaagg 1260 gaagacgatg
gatagtacag ttgccggaaa acactgatgg aggcggatgc tccagctcag 1320
ccaaagacct ttgttctgcc caccccagaa atgccccttc ctcaatcgca gaaacgttgc
1380 cccatggctc ctgatactca gaatgcagcc tctgaccagg accatctgca
tcctccagga 1440 gctcgtaaga aatgcagcat cgtgggacct gctggcacct
ggtgaaccca aacctgcagg 1500 gctcctgggt gtgcttgggg cggctgcagg
ggaagaggga gtcagcagcc tcctcctgac 1560 cttcccgggg gctgcttttc
tgaggggcca gaatgcaccg gttgaccttg ttgcatcact 1620 ggcccatgac
tggctgcttt ggtcaggtgt aaaaaggtgt ttccagaggg tctgctcctc 1680
tcactatcgg accaggtttc catggagagc tcagcctccc agcaaggata gagaacttca
1740 aatggctcaa agaactgaga ggccacacat gtgtgacctg aatagtctct
gctgcaaaac 1800 aaagggtttc ttaatgtaaa acgttctctt cctcacagag
gggttcccag ctgctagtgg 1860 gcatgttgca ggcatttcct gggctgcatc
aggttgtcat aagccagagg atcatttttg 1920 ggggctcat 1929 10 1167 DNA
Homo sapiens misc_feature sequence of STAR10 10 aggtcaggag
ttcaagacca gcctggccaa catggtgaaa ccctgtccct acaaaaaata 60
caaaaattag ccgggcgtgg tggggggcgc ctataatccc agctactcag gatgctgaga
120 caggagaatt gtttgaaccc gggaggtgga
ggttgcagtg aactgagatc gcgccactgc 180 actccagcct ggtgacagag
agagactccg tctcaacaac agacaaacaa acaaacaaac 240 aacaacaaaa
atgtttactg acagctttat tgagataaaa ttcacatgcc ataaaggtca 300
ccttctacag tatacaattc agtggattta gtatgttcac aaagttgtac gttgttcacc
360 atctactcca gaacatttac atcaccccta aaagaagctc tttagcagtc
acttctcatt 420 ctccccagcc cctgccaacc acgaatctac tntctgtctc
tattctgaat atttcatata 480 aaggagtcct atcatatggg ccttttacgt
ctaccttctt tcacttagca tcatgttttt 540 aagattcatc cacagtgtag
cacgtgtcag ttaattcatt tcatcttatg gctggataat 600 gctctattgt
atgcatatcc ctcactttgc ttatccattc atcaactgat tgacatttgg 660
gttatttcta ctttttgact attatgagta atgctgctat gaacattcct gtaccaatcg
720 ttacgtggac atatgctttc aattctcctg agtatgtaac tagggttgga
gttgctgggt 780 catatgttaa ctcagtgttt catttttttg aagaactacc
aaatggtttt ccaaagtgga 840 tgcaacactt tacattccca ccagcaagat
atgaaggttc caatgtctct acatttttgc 900 caacacttgt gattttcttt
tatttattta tttatttatt tatttttgag atggagtctc 960 actctgtcac
ccaggctgga gtgcagtggc acaatttcag ctcactgcaa tctccacctc 1020
tcgggctcaa gcgatactcc tgcctcaacc tcccgagtaa ctgggattac aggcgcccac
1080 caccacacca agctaatttt ttgtattttt agtagagacg gggtttcatc
atgtcggcca 1140 ggntgtactc gaactctgac ctcaagt 1167 11 1377 DNA Homo
sapiens misc_feature sequence of STAR11 11 aggatcactt gagcccagga
gttcaagacc agcctgggca acatagcgag aacatgtctc 60 aaaaaggaaa
aaaatggggg aaaaaaccct cccagggaca gatatccaca gccagtcttg 120
ataagctcca tcattttaaa gtgcaaggcg gtgcctccca tgtggatgat tatttaatcc
180 tcttgtactt tgtttagtcc tttgtggaaa tgcccatctt ataaattaat
agaattctag 240 aatctaatta aaatggttca actctacatt ttactttagg
ataatatcag gaccatcaca 300 gaatgtctga gatgtggatt taccctatct
gtagctcact tcttcaacca ttcttttagc 360 aaggctagtt atcttcagtg
acaacccctt gctgccctct actatctcct ccctcagatg 420 gactactctg
attaagcttg agctagaata agcatgttat cccgggattt catatggaat 480
attttataca tgagtgagcc attatgagtt gtttgaaaat ttattatgtt gagggagggt
540 aaccgctgta acaaccatca ccaaatctaa tcgactgaat acatttgacg
tttatttctt 600 gttcacctga cagttcagtg ttacctaaat ttacatgaag
acccagaggc ccacgctcct 660 tcattttggg ctccaccgac ctccaaggtt
tcagggccct ctgccccgcc ttctgcaccc 720 acaggggaag agagtggagg
atgcacacgc ccaggcctgg aagtgacgca tgtggcttcc 780 ccgtccacag
acttcaccca cagtccattg gccttcttaa gtcatggact cctgctgagc 840
tgccagggtg catgggaaat ccatgtgact gtgtgccctg gaggaagggg agcgtttcgg
900 tgagcacaca ggagtctttg ccactagacg ctgatgagga ttccccacag
gcgatgaagc 960 atggagactc atcttgtaac aaacagatga gttgttgaca
tctcttaagt ttactttgtg 1020 tgcagttttt attcagatag gaaaggctgt
taaaatctta acacctaact ggaagaaggg 1080 ttttagagaa gtgtggtttt
cagtaagcca gttctttcca caatccaaga aacgaaataa 1140 atttccagca
tggagcagtt ggcaggtaag gtttttgttg tggtctcgcc caggcttgag 1200
tgtaaccggt gtggtcatag ctcactacat tctcaaactc ctggccttaa gtcatcctcc
1260 tgcctcagcc tcccaaaggc aagtaaggtt aagaataggg gaaaggtgaa
gtttcacagc 1320 ttttctagaa ttctttttat tcaagggact ctcagatcat
caaacccacc cagaatc 1377 12 1051 DNA Homo sapiens misc_feature
sequence of STAR12 12 atcctgcttc tgggaagaga gtggcctccc ttgtgcaggt
gactttggca ggaccagcag 60 aaacccaggt ttcctgtcag gaggaagtgc
tcagcttatc tctgtgaagg gtcgtgataa 120 ggcacgagga ggcaggggct
tgccaggatg ttgcctttct gtgccatatg ggacatctca 180 gcttacgttg
ttaagaaata tttggcaaga agatgcacac agaatttctg taacgaatag 240
gatggagttt taagggttac tacgaaaaaa agaaaactac tggagaagag ggaagccaaa
300 caccaccaag tttgaaatcg attttattgg acgaatgtct cactttaaat
ttaaatggag 360 tccaacttcc ttttctcacc cagacgtcga gaaggtggca
ttcaaaatgt ttacacttgt 420 ttcatctgcc tttttgctaa gtcctggtcc
cctacctcct ttccctcact tcacatttgt 480 cgtttcatcg cacacatatg
ctcatcttta tatttacata tatataattt ttatatatgg 540 cttgtgaaat
atgccagacg agggatgaaa tagtcctgaa aacagctgga aaattatgca 600
acagtgggga gattgggcac atgtacattc tgtactgcaa agttgcacaa cagaccaagt
660 ttgttataag tgaggctggg tggtttttat tttttctcta ggacaacagc
ttgcctggtg 720 gagtaggcct cctgcagaag gcattttctt aggagcctca
acttccccaa gaagaggaga 780 gggcgagact ggagttgtgc tggcagcaca
gagacaaggg ggcacggcag gactgcagcc 840 tgcagagggg ctggagaagc
ggaggctggc acccagtggc cagcgaggcc caggtccaag 900 tccagcgagg
tcgaggtcta gagtacagca aggccaaggt ccaaggtcag tgagtctaag 960
gtccatggtc agtgaggctg agacccaggg tccaatgagg ccaaggtcca gagtccagta
1020 aggccgagat ccagggtcca gggaggtcaa g 1051 13 1291 DNA Homo
sapiens misc_feature sequence of STAR13 13 agccactgag gtcctaactg
cagccaaggg gccgttctgc acatgtcgct caccctctgt 60 gctctgttcc
ccacagagca aacgcacatg gcaacgttgg tccgctcagc cactggttct 120
gtggtggaac ggtggatgtc tgcactgtga catcagctga gtaagtaaca acgactgagg
180 atgccgctga cccagggctg gggaagggga ctcccagctc agacaggctt
ggctgtggtt 240 tgctttggga ggagagtgaa catcacaggg aatggctcat
gtcagcccca ggagggtggg 300 ctggcccctg gtccccgggc tccttctggc
cctgcaggcg atagagagcc tcaacctgct 360 gccgcttctc cttggcccgg
gtgatggccg tctggaagag cctgcagtag aggtgcacag 420 ccagcggaga
gtcgtcattg ccgggtacag ggtaggtgat gaggcagggg ttgcagttgg 480
tgtccacgat gcccactgtg gggatgttca tcttggctgc gtctctcacg gccacgtgtg
540 gctcaaagat gttgttgagc gtgtgcagga agatgatgag gtccggcagg
cggaccgtgg 600 ggccaaagag gaggcgcgcg ttggtcagca tgccgcccct
gaagtagcga gtgtgggcgt 660 actcgccaca gtcacgggcc atgttctcaa
tcaggtacga gaactgccgg ttgcggctta 720 taaacaagat gatgcccttg
cggtaggcca tgtgggcggt gaagttcaag gccagctgga 780 ggtgcgtggc
tgtctgttcc aggtcgatga tgtcgtggtc caggcggctc ccaaagatgt 840
acggctccat aaacctgcca gagaccccac caaggcaagg gggatgagag ttcacggggc
900 catctccact ggctccttgc aggaacacag acgcccacca gggactcccg
ggctcctctg 960 tgggggcact atgggctggg aagcacaatt tgcaacgctc
cccgtgtgca tggacagcag 1020 tgcagaccca tccaggccac ccctctgcat
gcctcgtctc gtggcttaac ccctcctacc 1080 ctctacctct tcccgaagga
atcctaatag aactgacccc atatggatgt gtggacatcc 1140 aacatgacgc
caaaaggaca ttctgccccg tgcagctcac agggcagccg cctccgtcac 1200
tgtcctcttc ccgaggcttt gcggatgagg cccctctggg gttggactta gcggggtgct
1260 ctgggccaaa agcattaagg gatcagggca g 1291 14 711 DNA Homo
sapiens misc_feature sequence of STAR14 14 ccctggacca gggtccgtgg
tcttggtggg cactggcttc ttcttgctgg gtgttttcct 60 gtgggtctct
ggcaaggcac tttttgtggc gctgcttgtg ctgtgtgcgg gaggggcagg 120
tgctctttcc tcttggagct ggaccctctg gggcgggtcc ccgtcggcct ccttgtgtgt
180 tttctgcacc tggtacagct ggatggcctc ctcaatgccg tcgtcgctgc
tggagtcgga 240 cgcctcgggc gcctgtacgg cgctcgtgac tcgctttccc
ctccttgcgg tgctggcgtt 300 ccttttaatc ccacttttat tctgtactgc
ttctgaaggg cggtgggggt tgctggcttt 360 gtgctgccct ccttctcctg
cgtggtcgtg gtcgtgacct tggacctgag gcttctgggc 420 tgcacgtttg
tctttgctaa ccgggggagg tctgcagaag gcgaactcct tctggacgcc 480
catcaggccc tgccggtgca ccacctttgt agccggctct tggtgggatt tcgagagtga
540 cttcgccgaa ttttcatgtg tgtctggttt cttctccact gacccatcac
atttttgggt 600 ctcatgctgt cttttctcat tcagaaactg ttctatttct
gccctgatgc tctgctcaaa 660 ggagtctgct ctgctcatgc tgactgggga
ggcagagccc tggtccttgc t 711 15 1876 DNA Homo sapiens misc_feature
sequence of STAR15 15 gagtccaaga tcaaggtgcc agcatcttgt gagggccttc
ttgttacgtc actccctagc 60 gaaagggcaa agagagggtg agcaagagaa
aggggggctg aactcgtcct tgtagaagag 120 gcccattccc gagacaatgg
cattcatcca ttcactccac cctcatggcc tcaccacctc 180 tcatgaggct
ccacctccca gccctggttt gttggggatt aaatttccaa cacatgcctt 240
ttgggggaca tgttaaaatt atagcacccc aaatgttaca ctatcttttg atgagcggta
300 gttctgattt taagtctagc tggcctactt tttcttgcac gtgggatgct
ttctgcctgt 360 tccagggcag gcagctcttc tctgtccctc tgctggcccc
acctcatcct ctgttgtcct 420 cttccctcct tctgtgccct ggggtcctgg
tgggggtgtg actgtcaact gcgttgggct 480 aacttttttc cctgctggtg
gcccgtaatg aaagaaagct tcttgctccc aagttcctta 540 aatccaagct
catagacaac gcggtctcac agcaggcctg gggccagcct cacgtgagcc 600
ccttccctgg tgtagtcact ggcatggggg aatgggattt cctgttgccc tactgtgtgg
660 ctgaggtggg ggttgcttcc tggagccagg ccttgtggaa gggcagtgcc
cactgcagtg 720 gatgctgggc cctgaatctg accccagtgt tcattggctc
tgtgagaccc agtgagggca 780 gggagggaag tggagctggg gtgagaagta
gaggccctgc agggcccacg tgccagccac 840 caggcctcag actaggctca
gatgacggag agctgcacac ctgcccaacc caggccctgc 900 agtgcccaca
tgccagccgc tggggcccag acttgctcca gagggcggag agctttacac 960
cggcccaacc caggccatgg ctccaaatgc gtgacagttt tgctgttgct tcttttagtc
1020 attgtcaagt tgatgcttgt tttgcagagg accaaggctt tatgaaccta
ttaccctgtg 1080 tgaagagttt caccaggtta tggaaatttc tttaaaacca
taccacagtt ttttcattat 1140 tcatgtatat ttttaaaaat aattactgca
ctcagtagaa taacatgaaa atgttgcctg 1200 ttagcccttt tccagtttgc
cccgagaata ctgggggcac ttgtggctgc aatgtttatc 1260 ctgcggcagc
tttgccatga agtatctcac ttttattatt atttttgcat tgctcgagta 1320
tattgacttt ggaaacaaaa gacatcattc tatttatagc attatgtttt tagtagtggt
1380 atttccatat acaagataca gtaattttcc gtcaatgaaa atgtcaaatt
ctagaaaatg 1440 taacattcct atgcgtggtg ttaacatcgt tctctaacag
ttgttggccg aagattcgtt 1500 tgatgaatcc gatttttcca aaatagccga
ttctgatgat tcagacgatt ctgatgttct 1560 gtttagaaat aattccaaga
acagttttta cattttattt tcacattgaa aatcagtcag 1620 atttgcttca
gcctcaaaga gcacgtttat gtaaaattaa atgagtgctg gcagccagct 1680
gcgctttgtt tttctaaatg ggaaaagggt taaatttcac tcagctttta aatgacagcg
1740 cacagcctgt gtcatagagg gttggaggag atgactttaa ctgcctgtgg
ttaggatccc 1800 tttcccccag gaatgtctgg gagcccactg ccgggtttgc
tgtccgtctc gtttggactc 1860 agttctgcat gtactg 1876 16 1282 DNA Homo
sapiens misc_feature sequence of STAR16 16 cgcccacctc ggctttccaa
agtgctggga ttacaggcat gagtcactgc gcccatcctg 60 attccaagtc
tttagataat aacttaactt tttcgaccaa ttgccaatca ggcaatcttt 120
gaatctgcct atgacctagg acatccctct ccctacaagt tgccccgcgt ttccagacca
180 aaccaatgta catcttacat gtattgattg aagttttaca tctccctaaa
acatataaaa 240 ccaagctata gtctgaccac ctcaggcacg tgttctcagg
acctccctgg ggctatggca 300 tgggtcctgg tcctcagatt tggctcagaa
taaatctctt caaatatttt ccagaatttt 360 actcttttca tcaccattac
ctatcaccca taagtcagag ttttccacaa ccccttcctc 420 agattcagta
atttgctaga atggccacca aactcaggaa agtattttac ttacaattac 480
caatttatta tgaagaactc aaatcaggaa tagccaaatg gaagaggcat agggaaaggt
540 atggaggaag gggcacaaag cttccatgcc ctgtgtgcac accaccctct
cagcatcttc 600 atgtgttcac caactcagaa gctcttcaaa ctttgtcatt
taggggtttt tatggcagtt 660 ccactatgta ggcatggttg ataaatcact
ggtcatcggt gatagaactc tgtctccagc 720 tcctctctct ctcctcccca
gaagtcctga ggtggggctg aaagtttcac aaggttagtt 780 gctctgacaa
ccagccccta tcctgaagct attgaggggt cccccaaaag ttaccttagt 840
atggttggaa gaggcttatt atgaataaca aaagatgctc ctatttttac cactagggag
900 catatccaag tcttgcggga acaaagcatg ttactggtag caaattcata
caggtagata 960 gcaatctcaa ttcttgcctt ctcagaagaa agaatttgac
caagggggca taaggcagag 1020 tgagggacca agataagttt tagagcagga
gtgaaagttt attaaaaagt tttaggcagg 1080 aatgaaagaa agtaaagtac
atttggaaga gggccaagtg ggcgacatga gagagtcaaa 1140 caccatgccc
tgtttgatgt ttggcttggg gtcttatatg atgacatgct tctgagggtt 1200
gcatccttct cccctgattc ttcccttggg gtgggctgtc cgcatgcaca atggcctgcc
1260 agcagtaggg aggggccgca tg 1282 17 793 DNA Homo sapiens
misc_feature sequence of STAR17 17 atccgagggg aggaggagaa gaggaaggcg
agcagggcgc cggagcccga ggtgtctgcg 60 agaactgttt taaatggttg
gcttgaaaat gtcactagtg ctaagtggct tttcggattg 120 tcttatttat
tactttgtca ggtttcctta aggagagggt gtgttggggg tgggggagga 180
ggtggactgg ggaaacctct gcgtttctcc tcctcggctg cacagggtga gtaggaaacg
240 cctcgctgcc acttaacaat ccctctatta gtaaatctac gcggagactc
tatgggaagc 300 cgagaaccag tgtcttcttc cagggcagaa gtcacctgtt
gggaacggcc cccgggtccc 360 cctgctgggc tttccggctc ttctaggcgg
cctgatttct cctcagccct ccacccagcg 420 tccctcaggg acttttcaca
cctccccacc cccatttcca ctacagtctc ccagggcaca 480 gcacttcatt
gacagccaca cgagccttct cgttctcttc tcctctgttc cttctctttc 540
tcttctcctc tgttccttct ctttctctgt cataatttcc ttggtgcttt cgccacctta
600 aacaaaaaag agaaaaaaat aaaataaaaa aaacccattc tgagccaaag
tattttaaga 660 tgaatccaag aaagcgaccc acatagccct ccccacccac
ggagtgcgcc aagacgcacc 720 caggctccat cacagggccg agagcagcgc
cactctggtc gtacttttgg gtcaagagat 780 cttgcaaaag agg 793 18 492 DNA
Homo sapiens misc_feature sequence of STAR18 18 atctttttgc
tctctaaatg tattgatggg ttgtgttttt tttcccacct gctaataaat 60
attacattgc aacattcttc cctcaacttc aaaactgctg aactgaaaca atatgcataa
120 aagaaaatcc tttgcagaag aaaaaaagct attttctccc actgattttg
aatggcactt 180 gcggatgcag ttcgcaaatc ctattgccta ttccctcatg
aacattgtga aatgaaacct 240 ttggacagtc tgccgcattg cgcatgagac
tgcctgcgca aggcaagggt atggttccca 300 aagcacccag tggtaaatcc
taacttatta ttcccttaaa attccaatgt aacaacgtgg 360 gccataaaag
agtttctgaa caaaacatgt catctttgtg gaaaggtgtt tttcgtaatt 420
aatgatggaa tcatgctcat ttcaaaatgg aggtccacga tttgtggcca gctgatgcct
480 gcaaattatc ct 492 19 1840 DNA Homo sapiens misc_feature
sequence of STAR19 19 tcacttcctg atattttaca ttcaaggcta gctttatgca
tatgcaacct gtgcagttgc 60 acagggcttt gtgttcagaa agactagctc
ttggtttaat actctgttgt tgccatcttg 120 agattcatta taatataatt
tttgaatttg tgttttgaac gtgatgtcca atgggacaat 180 ggaacattca
cataacagag gagacaggtc aggtggcagc ctcaattcct tgccaccctt 240
ttcacataca gcattggcaa tgccccatga gcacaaaatt tgggggaacc atgatgctaa
300 gactcaaagc acatataaac atgttacctc tgtgactaaa agaagtggag
gtgctgacag 360 cccccagagg ccacagttta tgttcaaacc aaaacttgct
tagggtgcag aaagaaggca 420 atggcagggt ctaagaaaca gcccatcata
tccttgttta ttcatgttac gtccctgcat 480 gaactaatca cttacactga
aaatattgac agaggaggaa atggaaagat agggcaaccc 540 atagttcttt
ttccttttag tctttcctta tcagtaaacc aaagatagta ttggtaaaat 600
gtgtgtgagt taattaatga gttagtttta ggcagtgttt ccactgttgg ggtaagaaca
660 aaatatatag gcttgtattg agctattaaa tgtaaattgt ggaatgtcag
tgattccaag 720 tatgaattaa atatccttgt atttgcattt aaaattggca
ctgaacaaca aagattaaca 780 gtaaaattaa taatgtaaaa gtttaatttt
tacttagaat gacattaaat agcaaataaa 840 agcaccatga taaatcaaga
gagagactgt ggaaagaagg aaaacgtttt tattttagta 900 tatttaatgg
gactttcttc ctgatgtttt gttttgtttt gagagagagg gatgtggggg 960
cagggaggtc tcattttgtt gcccaggctg gacttgaact cctgggctcc agctatcctg
1020 ccttagcttc ttgagtagct gggactacag gcacacacca cagtgtctga
cattttctgg 1080 attttttttt tttttttatt ttttttgtga gacaggttct
ggctctgtta ctcaggttgc 1140 agtgcagtgg catgatagcg gctcactgca
gcctcaacct cctcagctta agctactctc 1200 ccacttcagc ctcctgagta
gccaggacta cagttgtgtg ccaccacacc tgtggctaat 1260 ttttgtagag
atggggtctc tccacgttgc cgaggctggt ctccaactcc tggtctcaag 1320
cgaacctcct gacttggcct cccgaagtgc tgggattaca ggcttgagcc actgcatcca
1380 gcctgtcctc tgtgttaaac ctactccaat ttgtctttca tctctacata
aacggctctt 1440 ttcaaagttc ccatagacct cactgttgct aatctaataa
taaattatct gccttttctt 1500 acatggttca tcagtagcag cattagattg
ggctgctcaa ttcttcttgg tatattttct 1560 tcatttggct tctggggcat
cacactctct ttgagttact cattcctcat tgatagcttc 1620 ttcctagtct
tctttactgg ttcttcctct tctccctgac tccttaatat tgtttttctc 1680
cccaggcttt agttcttagt cctcttctgt tatctattta cacccaattc tttcagagtc
1740 tcatccagag tcatgaactt aaacctgttt ctgtgcagat aattcacatt
attatatctc 1800 cagcccagac tctcccgcaa actgcagact gatcctactg 1840 20
780 DNA Homo sapiens misc_feature sequence of STAR20 20 gatctcaagt
ttcaatatca tgttttggca aaacattcga tgctcccaca tccttaccta 60
aagctaccag aaaggctttg ggaactgtca acagagctac agaaaagtca gtaaagacca
120 atggacccct caaacaaaaa cagccaagct tttctgccaa aaagatgact
gagaagactg 180 ttaaagcaaa aaactctgtt cctgcctcag atgatggcta
tccagaaata gaaaaattat 240 ttcccttcaa tcctctaggc ttcgagagtt
ttgacctgcc tgaagagcac cagattgcac 300 atctcccctt gagtgaagtg
cctctcatga tacttgatga ggagagagag cttgaaaagc 360 tgtttcagct
gggcccccct tcacctttga agatgccctc tccaccatgg aaatccaatc 420
tgttgcagtc tcctttaagc attctgttga ccctggatgt tgaattgcca cctgtttgct
480 ctgacataga tatttaaatt tcttagtgct ttagagtttg tgtatatttc
tattaataaa 540 gcattatttg tttaacagaa aaaaagatat atacttaaat
cctaaaataa aataaccatt 600 aaaaggaaaa acaggagtta taactaataa
gggaacaaag gacataaaat gggataataa 660 tgcttaatcc aaaataaagc
agaaaatgaa gaaaaatgaa atgaagaaca gataaataga 720 aaacaaatag
caatatgaaa gacaaacttg accgggtgtg gtggctgatg cctgtaatcc 780 21 607
DNA Homo sapiens misc_feature sequence of STAR21 21 gatcaataat
ttgtaatagt cagtgaatac aaaggggtat atactaaatg ctacagaaat 60
tccattcctg ggtataaatc ctagacatat ttatgcatat gtacaccaag atatatctgc
120 aagaatgttc acagcaaatc tctttgtagt agcaaaaggc caaaaggtct
atcaacaaga 180 aaattaatac attgtggcac ataatggcat ccttatgcca
ataaaaatgg atgaaattat 240 agttaggttc aaaaggcaag cctccagata
atttatatca tataattcca tgtacaacat 300 tcaacaacaa gcaaaactaa
acatatacaa atgtcaggga aaatgatgaa caaggttaga 360 aaatgattaa
tataaaaata ctgcacagtg ataacattta atgagaaaaa aagaaggaag 420
ggcttaggga gggacctaca gggaactcca aagttcatgg taagtactaa atacataatc
480 aaagcactca aaatagaaaa tattttagta atgttttagc tagttaatat
cttacttaaa 540 acaaggtcta ggccaggcac ggtggctcac acctgtaatc
ccagcacttt gggaggctga 600 ggcgggt 607 22 1380 DNA Homo sapiens
misc_feature sequence of STAR22 22 cccttgtgat ccacccgcct tggcctccca
aagtgctggg attacaggcg tgagtcacta 60 cgcccggcca ccctccctgt
atattatttc taagtatact attatgttaa aaaaagttta 120 aaaatattga
tttaatgaat tcccagaaac taggatttta catgtcacgt tttcttatta 180
taaaaataaa aatcaacaat aaatatatgg taaaagtaaa aagaaaaaca aaaacaaaaa
240 gtgaaaaaaa taaacaacac tcctgtcaaa aaacaacagt tgtgataaaa
cttaagtgcc 300 tgaaaattta gaaacatcct tctaaagaag ttctgaataa
aataaggaat aaaataatca 360 catagttttg gtcattggtt ctgtttatgt
gatggattat gtttattgat ttgtgtatgt 420 tgaacttatc tcaatagatg
cagacaaggc cttgataaaa gtttttaaca ccttttcatg 480 ttgaaaactc
tcaatagact aggtattgat gaaacatatc tcaaaataat agaagctatt 540
tatgataaac ccatagccaa tatcatactg agtgggcaaa agctggaagc attccctttg
600 aaaactggca caagacaagg atgccctctc tcaccactcc tattaaatgt
agtattggaa 660 gttctggcca gagcaatcag gcaggagaaa gaaaaggtat
taaaatagga agagaggaag 720 tcaaattgtc tctgtttgca gtaaacatga
ttgtatattt agaaaacccc attgtctcat 780 cctaaaaact ccttaagctg
ataaacaact tcagcaaagt ctcaggatac aaaatcaatg 840 tgcaaaaatc
acaagcattc ctatacaccg
ataatagaca gcagagagcc aaatcatgag 900 tgaagtccca ttcacaattg
cttcaaagaa aataaaatac ttaggaatac aactttcacg 960 ggacatgaag
gacattttca aggacaacta aaaaccactg ctcaaggaaa tgagagagga 1020
cacaaagaaa tggaaaaaca ttccatgctc atggaagaat caatatcatg aaaatggcca
1080 tactgcccaa agtaatttat agattcaatg ctaaccccat caagccacca
ttgactttct 1140 tcacagaact agaaaaaaac tattttaaaa ctcatatgta
gtcaaaaaga gtcggtatag 1200 ccaagacaat cctaagcata aagaacaaag
ctggatgcat cacgctgact tcaaaccata 1260 ctacaaggct acagtaacca
aaacagcatg gtactggtac caaaacagat agatagaccg 1320 atagaacaga
acagaggcct cggaaataac accacacatc tacaaccctt tgatcttcaa 1380 23 1246
DNA Homo sapiens misc_feature sequence of STAR23 23 atcccctcat
ccttcagggc agctgagcag ggcctcgagc agctggggga gcctcactta 60
atgctcctgg gagggcagcc agggagcatg gggtctgcag gcatggtcca gggtcctgca
120 ggcggcacgc accatgtgca gccgccccca cctgttgctc tgcctccgcc
acctggccat 180 gggcttcagc agccagccac aaagtctgca gctgctgtac
atggacaaga agcccacaag 240 cagctagagg accttgtgtt ccacgtgccc
agggagcatg gcccacagcc caaagaccag 300 tcaggagcag gcaggggctt
ctggcaggcc cagctctacc tctgtcttca cacagatggg 360 agatttctgt
tgtgattttg agtgatgtgc ccctttggtg acatccaaga tagttgctga 420
agcaccgctc taacaatgtg tgtgtattct gaaaacgaga acttctttat tctgaaataa
480 ttgatgcaaa ataaattagt ttggatttga aattctattc atgtaggcat
gcacacaaaa 540 gtccaacatt gcatatgaca caaagaaaag aaaaagcttg
cattccttaa atacaaatat 600 ctgttaacta tatttgcaaa tatatttgaa
tacacttcta ttatgttaca tataatatta 660 tatgtatatg tatatataat
atacatatat atgttacata taatatactt ctattatgtt 720 acatataata
tttatctata agtaaataca taaatataaa gatttgagta gctgtagaac 780
attgtcttat gtgttatcag ctactactac aaaaatatct cttccactta tgccagtttg
840 ccatataaat atgatcttct cattgatggc ccagggcaag agtgcagtgg
gtacttattc 900 tctgtgagga gggaggagaa aagggaacaa ggagaaagtc
acaaagggaa aactctggtg 960 ttgccaaaat gtcaagtttc acatattccg
agacggaaaa tgacatgtcc cacagaagga 1020 ccctgcccag ctaatgtgtc
acagatatct caggaagctt aaatgatttt tttaaaagaa 1080 aagagatggc
attgtcactt gtttcttgta gctgaggctg tgggatgatg cagatttctg 1140
gaaggcaaag agctcctgct ttttccacac cgagggactt tcaggaatga ggccagggtg
1200 ctgagcacta caccaggaaa tccctggaga gtgtttttct tactta 1246 24 939
DNA Homo sapiens misc_feature sequence of STAR24 24 acgaggtcac
gagttcgaga ccagcctggc caagatggtg aagccctgtc tctactaaaa 60
atacaacaag tagccgggcg cggtgacggg cgcctgtaat cccagctact caggaggctg
120 aagcaggaga atctctagaa cccaggaggc ggaggtgcag tgagctgaga
ctgccccgct 180 gcactctagc ctgggcaaca cagcaagact ctgtctcaaa
taaataaata aataaataaa 240 taaataaata aataaataaa tagaaaggga
gagttggaag tagatgaaag agaagaaaag 300 aaatcctaga tttcctatct
gaaggcacca tgaagatgaa ggccacctct tctgggccag 360 gtcctcccgt
tgcaggtgaa ccgagttctg gcctccattg gagaccaaag gagatgactt 420
tggcctggct cctagtgagg aagccatgcc tagtcctgtt ctgtttgggc ttgatcctgt
480 atcacttgat tgtctctcct ggactttcca tggattccag ggatgcaact
gagaagttta 540 tttttaatgc acttacttga agtaagagtt attttaaaac
attttagcaa aggaaatgaa 600 ttctgacagg ttttgcactg aagacattca
catgtgagga aaacaggaaa accactatgc 660 tagaaaaagc aaatgctgtt
gagattgtct cacaaacaca aattgcgtgc cagcaggtag 720 gtttgagcct
caggttgggc acattttacc ttaagcgcac tgttggtgga acttaaggtg 780
actgtaggac ttatatatac atacatacat ataatatata tacatattta tgtgtatata
840 cacacacaca cacacacaca cacacagggt cttgctatct tgcccagggt
ggtctccaac 900 tctgggtctc aagcgatcct ctgcctcccc ttcccaaag 939 25
1067 DNA Homo sapiens misc_feature sequence of STAR25 25 cagcccctct
tgtgtttttc tttatttctc gtacacacac gcagttttaa gggtgatgtg 60
tgtataatta aaaggaccct tggcccatac tttcctaatt ctttagggac tgggattggg
120 tttgactgaa atatgttttg gtggggatgg gacggtggac ttccattctc
cctaaactgg 180 agttttggtc ggtaatcaaa actaaaagaa acctctggga
gactggaaac ctgattggag 240 cactgaggaa caagggaatg aaaaggcaga
ctctctgaac gtttgatgaa atggactctt 300 gtgaaaatta acagtgaata
ttcactgttg cactgtacga agtctctgaa atgtaattaa 360 aagtttttat
tgagcccccg agctttggct tgcgcgtatt tttccggtcg cggacatccc 420
accgcgcaga gcctcgcctc cccgctgccc tcagcctccg atgacttccc cgcccccgcc
480 ctgctcggtg acagacgttc tactgcttcc aatcggaggc acccttcgcg
ggagcggcca 540 atcgggagct ccggcaggcg gggaggccgg gccagttaga
tttggaggtt caacttcaac 600 atggccgaag caagtagcgc caatctaggc
agcggctgtg aggaaaaaag gcatgagggg 660 tcgtcttcgg aatctgtgcc
acccggcact accatttcga gggtgaagct cctcgacacc 720 atggtggaca
cttttcttca gaagctggtc gccgccggca ggtaaagtgg acgcagccgc 780
ggtgggagtg tttgttggca ccgaagctca aatcccgcga ggtcaggacg gccgcaggct
840 ggcgcgcggt gacgtgggtc cgcgttgggg gcggggcagt cggacgaggc
gacccagtca 900 aatcctgagc cttaggagtc agggtattca cgcactgata
acctgtagcg gaccgggata 960 gctagctact ccttcctaca ggaagccccg
ttttcactaa aatttcaggt ggttgggagg 1020 aaagatagag cctttgcaaa
ttagagcagg gttttttatt tttttat 1067 26 540 DNA Homo sapiens
misc_feature sequence of STAR26 26 ccccctgaca agccccagtg tgtgatgttc
cccactctgt gtccatgcat tctcattgtt 60 caactcccat ctgtgagtga
gaacatgcag tgtttggttt tctgtccttg agatagtttg 120 ctgagaatga
tggtttccag cttcatccat gtccttgcaa aggaagtgaa cttatccttt 180
tttatggctt catagtattc catggcacat atgtgccaca tttttttaat ccagtctatc
240 attgatggac atttgggttg gttccaagtc tttgctattg tgaatagcac
cacaattaac 300 atatgtgtgc atgtatacat ctttatagta gcatgattta
taatccttcg ggtatatacc 360 ctgtaatggg atcgctgggt caaatggtat
ttctagttct agatccttga ggaatcacca 420 cactgctttc cacaatggtt
gaactaattt acgctcccac cagcagtgta aaagcattcc 480 tatttctcca
cgtcctctcc agtatctgtt gtttcctgac tttttaatga tcatcattct 540 27 1520
DNA Homo sapiens misc_feature sequence of STAR27 27 cttggccctc
acaaagcctg tggccaggga acaattagcg agctgcttat tttgctttgt 60
atccccaatg ctgggcataa tgcctgccat tatgagtaat gccggtagaa gtatgtgttc
120 aaggaccaaa gttgataaat accaaagaat ccagagaagg gagagaacat
tgagtagagg 180 atagtgacag aagagatggg aacttctgac aagagttgtg
aagatgtact aggcaggggg 240 aacagcttaa ggagagtcac acaggaccga
gctcttgtca agccggctgc catggaggct 300 gggtggggcc atggtagctt
tcccttcctt ctcaggttca gagtgtcagc cttgaacttc 360 taattcccag
aggcatttat tcaatgtttt cttctagggg catacctgcc ctgctgtgga 420
agactttctt ccctgtgggt cgccccagtc cccagatgag acggtttggg tcagggccag
480 gtgcaccgtt gggtgtgtgc ttatgtctga tgacagttag ttactcagtc
attagtcatt 540 gagggaggtg tggtaaagat ggagatgctg ggtcacatcc
ctagagaggt gttccagtat 600 gggcacatgg gagggctgga aggataggtt
actgctagac gtagagaagc cacatccttt 660 aacaccctgg cttttcccac
tgccaagatc cagaaagtcc ttgtggtttc gctgctttct 720 cctttttttt
tttttttttt tttctgagat ggagtctggc tctgtcgccc aggctggagt 780
gcagtggcac gatttcggct cactgcaagt tccgcctcct aggttcatac cattctccca
840 cctcagcctc ccgagtagct gggactacag gcgccaccac acccagctaa
ttttttgtat 900 ttttagtaga gacggcgttt caccatgtta gccaggatgg
tcttgatccg cctgcctcag 960 cctcccaaag tgctgggatt acaggcgtga
gccaccgcgc ccggcctgct ttcttctttc 1020 atgaagcatt cagctggtga
aaaagctcag ccaggctggt ctggaactct tgacctcaag 1080 tgatctgcct
gcctcagcct cccaaagtgc tgagattaca ggcatgagcc agtccgaatg 1140
tggctttttt tgttttgttt tgaaacaagg tctcactgtt gcccaggctg cagtgcagtg
1200 gcatacctca gctccactgc agcctcgacc tcctgggctc aagcaatcct
cccaactgag 1260 cctccccagt agctggggct acaagcgcat gccaccacgc
ctggctattt tttttttttt 1320 tttttttttt gagaaggagt ttcattcttg
ttgcccaggc tggagtgcaa tggcacagtc 1380 tcagctcact gcagcctccg
cctcctgggt tcaagcgatt ctcctgcctc agcctcccga 1440 gtagctggga
ttataggcac ctgccaccat gcctggctaa tttttttgta tttttagtag 1500
ggatggggtt tcaccatgtt 1520 28 961 DNA Homo sapiens misc_feature
sequence of STAR28 28 aggaggttat tcctgagcaa atggccagcc tagtgaactg
gataaatgcc catgtaagat 60 ctgtttaccc tgagaagggc atttcctaac
tctccctata aaatgccaag tggagcaccc 120 cagatgaaat agctgatatg
ctttctatac aagccatcta ggactggctt tatcatgacc 180 aggatattca
cccactgaat atggctatta cccaagttat ggtaaatgct gtagttaagg 240
gggtcccttc cacatggaca ccccaggtta taaccagaaa gggttcccaa tctagactcc
300 aagagagggt tcttagacct catgcaagaa agaacttggg gcaagtacat
aaagtgaaag 360 caagtttatt aagaaagtaa agaaacaaaa aaatggctac
tccataagca aagttatttc 420 tcacttatat gattaataag agatggatta
ttcatgagtt ttctgggaaa ggggtgggca 480 attcctggaa ctgagggttc
ctcccacttt tagaccatat agggtatctt cctgatattg 540 ccatggcatt
tgtaaactgt catggcactg atgggagtgt cttttagcat tctaatgcat 600
tataattagc atataatgag cagtgaggat gaccagaggt cacttctgtt gccatattgg
660 tttcagtggg gtttggttgg cttttttttt tttttaacca caacctgttt
tttatttatt 720 tatttattta tttatttatt tatatttttt attttttttt
agatggagtc ttgctctgtc 780 acccaggtta gagtgcagtg gcaccatctc
ggctcactgc aagctctgcc tccttggttc 840 acgccattct gctgcctcag
cctcccgagt agctgggact acaggtgcct gccaccatac 900 ccggctaatt
ttttctattt ttcagtagag acggggtttc accgtgttag ccaggatggt 960 c 961 29
2233 DNA Homo sapiens misc_feature sequence of STAR29 29 agcttggaca
cttgctgatg ccactttgga tgttgaaggg ccgccctctc ccacaccgct 60
ggccactttt aaatatgtcc cctctgccca gaagggcccc agaggagggg ctggtgaggg
120 tgacaggagt tgactgctct cacagcaggg ggttccggag ggaccttttc
tccccattgg 180 gcagcataga aggacctaga agggccccct ccaagcccag
ctgggcgtgc agggccagcg 240 attcgatgcc ttcccctgac tcaggtggcg
ctgtcctaaa ggtgtgtgtg ttttctgttc 300 gccagggggt ggcggataca
gtggagcatc gtgcccgaag tgtctgagcc cgtggtaagt 360 ccctggaggg
tgcacggtct cctccgactg tctccatcac gtcaggcctc acagcctgta 420
ggcaccgctc ggggaagcct ctggatgagg ccatgtggtc atccccctgg agtcctggcc
480 tggcctgaag aggaggggag gaggaggcca gcccctccct agccccaagg
cctgcgaggc 540 tgcaagcccg gccccacatt ctagtccagg cttggctgtg
caagaagcag attgcctggc 600 cctggccagg cttcccagct aggatgtggt
atggcagggg tgggggacat tgaggggctg 660 ctgtagcccc cacaacctcc
ccaggtaggg tggtgaacag taggctggac aagtggacct 720 gttcccatct
gagattcaag agcccacctc tcggaggttg cagtgagccg agatccctcc 780
actgcactcc agcctgggca acagagcaag actctgtctc aaaaaaacag aacaacgaca
840 acaaaaaacc cacctctggc ccactgccta actttgtaaa taaagtttta
ttggcacata 900 gacacaccca ttcatttaca tactgctgcg gctgcttttg
cattaccctt gagtagacga 960 cagaccacgt ggccatggaa gccaaaaata
tttactgtct ggccctttac agaagtctgc 1020 tctagaggga gaccccggcc
catggggcag gaccactggg cgtgggcaga agggaggcct 1080 cggtgcctcc
acgggcctag ttgggtatct cagtgcctgt ttcttgcatg gagcaccagg 1140
ggtcagggca agtacctgga ggaggcaggc tgttgcccgc ccagcactgg gacccaggag
1200 accttgagag gctcttaacg aatgggagac aagcaggacc agggctccca
ttggctgggc 1260 ctcagtttcc ctgcctgtaa gtgagggagg gcagctgtga
aggtgaactg tgaggcagag 1320 cctctgctca gccattgcag gggcggctct
gccccactcc tgttgtgcac ccagagtgag 1380 gggcacgggg tgagatgtca
ccatcagccc ataggggtgt cctcctggtg ccaggtcccc 1440 aagggatgtc
ccatcccccc tggctgtgtg gggacagcag agtccctggg gctgggaggg 1500
ctccacactg ttttgtcagt ggtttttctg aactgttaaa tttcagtgga aaattctctt
1560 tcccctttta ctgaaggaac ctccaaagga agacctgact gtgtctgaga
agttccagct 1620 ggtgctggac gtcgcccaga aagcccaggt actgccacgg
gcgccggcca ggggtgtgtc 1680 tgcgccagcc atgggcacca gccaggggtg
tgtctacgcc ggccaggggt aggtctccgc 1740 cggcctccgc tgctgcctgg
ggagggccgt gcctgacact gcaggcccgg tttgtccgcg 1800 gtcagctgac
ttgtagtcac cctgcccttg gatggtcgtt acagcaactc tggtggttgg 1860
ggaaggggcc tcctgattca gcctctgcgg acggtgcgcg agggtggagc tcccctccct
1920 ccccaccgcc cctggccagg gttgaacgcc cctgggaagg actcaggccc
gggtctgctg 1980 ttgctgtgag cgtggccacc tctgccctag accagagctg
ggccttcccc ggcctaggag 2040 cagccgggca ggaccacagg gctccgagtg
acctcagggc tgcccgacct ggaggccctc 2100 ctggcgtcgc ggtgtgactg
acagcccagg agcgggggct gttgtaattg ctgtttctcc 2160 ttcacacaga
accttttcgg gaagatggct gacatcctgg agaagatcaa gaagtaagtc 2220
ccgcccccca ccc 2233 30 1851 DNA Homo sapiens misc_feature sequence
of STAR30 30 gggtgcattt ccacccaggg gacacttggc aatggtggga gacattgctt
gttgtcacaa 60 ctgggcatgg gagtgctgct gcgtctagtg ggtagaggcc
agagatgctc ctaatatcct 120 acaaggcaca gaacagcccc ccacaacaga
gaattatcca gcctgaaaat gtccacagtg 180 ctgaggttgg gaaaccctat
tctagagcca acaggctgtg aagcttgact catggttcca 240 tcaccaatag
ctgcgtgacc ttggtgagtt ccttagctgc tctgtgcctc ggattcatgg 300
taggttttcc ttgttaggtt taaatgagtg aagttataca gagggcctga agtctcatgg
360 tattttacta gagcctcatt gtgttttagt tataattaga aattgggtaa
ggtaaggaca 420 cagaagaagc catctgatct gggggcttca cacttagaag
tgacctcgga gcaattgtat 480 tggggtggaa agggactaac agccaggagc
agagggcaca ttggaattgg ggccagaggg 540 cacagactgc cttgtccatc
aggcatagca atggacagag gaaggggaat gactagttat 600 ggctgcaagg
ccaagtacag gggacttatt tctcatatct atctatctat ctacctaccg 660
tctatttatc tatcatctat ctacttattt atctatctat ttatgcatgt gtaccaaccg
720 aaagttttag taaatgcaca aactgcgata taatgaaaat ggaaattttc
aaaagaagag 780 aaatcacctg ccacctgact accttaacaa atgagtggtt
ttcatctctc cttccaggcc 840 tgtcattttt acagtgcttt agtcataaaa
caggtcctct attctattgt tttatgtcac 900 atgaaattgt accataagca
ttttccatga tgtgactcca ctgtttcatt ttccattttt 960 ttccagaatg
aagataacct cattgttttt ttcctgattg taaaaatgct ctgtgctctt 1020
tttttttttt tttaacaatg caggcagtac caaaaagtat gaagaagaat gtaatagttc
1080 ccatttccca tctcactctt taaggccagc attttggtga acatccatcc
gaacaaatct 1140 ccacgcgttt atcaatttgt tgacttactc cttcttttat
gtaaatatga acatgattta 1200 actgccagtc catttggaac cttaaagtga
aggtttttta ttgttggggt ttgctatggt 1260 ctgaatatgt gtgtcccccc
aaaatttatg ttgaatccta acgcccaatg cgattaggag 1320 gtggggccat
taggaggtga ttaagtcatg aagtcatcag ccctaatgaa tgggatttgt 1380
ggccttgaaa agggacccca gagagctgcc ttgccccttc tgccatgtaa ggacacagtg
1440 aggagctagg aagggggcct cagcagagac caaatgtgat ggtgcctcga
tattggactt 1500 cccagcctcc agaatgtgag aaatgaattt ctgttgttta
taagtcaccc agtctatagt 1560 attttgttct agcagcccaa acagactaag
tcagggttgt tgttttagga agtggggaat 1620 ggggccatgc atgggtgtac
gccagaacaa aggaagccag caagtcctga aagatactgg 1680 aaaagggaat
agtgggcacg tgcagtgtgt tagtttcctg aggctgctat aacaaagcac 1740
cacaggttgg gtggcttaaa taacagaaat tcattctccc atcattctgg ggaccagacg
1800 tctgaaatca agactcctat gccatgctcc ttctgaaggc tccaggggag g 1851
31 1701 DNA Homo sapiens misc_feature sequence of STAR31 31
cacccgcctt ggccccccag agtgctggga ttacaagtgt aaaccaccat tcctggctag
60 atttaatttt ttaaaaaata aagagaagta ggaatagttc attttaggga
gagcccctta 120 actgggacag gggcaggaca ggggtgaggc ttcccttant
tcaagctcac ctcaaaccca 180 cccaggactg tgtgtcacat tctccaataa
aggaaaggtt gctgcccccg cctgtgagtg 240 ctgcagtgga gggtagaggg
ccgtgggcag agtgcttcat ggactgctca tcaagaaagg 300 cttcatgaca
atcggcccag ctgctgtcat cccacattct acttccagct aggagaaggc 360
ggcttgccca cagtcaccca gccggcaagt gtcacccctg ggttggaccc agagctatga
420 tcctgcccag gggtccagct gagaatcagg cccacgttct aggcagaggg
gctcacctac 480 tgggactcca gtagctgtag tgcatggagg catcatggct
gcagcagcct ggacctggtc 540 tcacactggc tgtccctgtg ggcaggccat
cctcaatgcc aggtcaggcc caagcatgta 600 tcccagacaa tgacaatggg
gtggaatcct ctcttgtccc agaagccact cctcactgtt 660 ctacctgagg
aaggcagggg catggtggaa tcctgaagcc tgctgtgagg gtctccagcg 720
aacttgcaca tggtcagccc tgccttctcc tccctgaact agattgagcg agagcaagaa
780 ggacattgaa ccagcaccca aagaattttg gggaacggcc tctcatccag
gtcaggctca 840 cctccttttt aaaatttaat taattaatta attaattttt
ttttagagac agagtcttac 900 tgtgtggccc aggctgtagt gcagtggcac
aatcatagtt cactgcagcc tcaaactccc 960 cacctcagcc tctggattag
ctgagactac aggtgcacca ccaccacacc cagctaatat 1020 ttttattttt
gtagagagag ggtttcacca tcttgcccag gctggtctca aactcctggg 1080
ctcaagtgat cccgcccagg tctgaaagcc cccaggctgg cctcagactg tggggttttc
1140 catgcagcca cccgagggcg cccccaagcc agttcatctc ggagtccagg
cctggccctg 1200 ggagacagag tgaaaccagt ggtttttatg aacttaactt
agagtttaaa agatttctac 1260 tcgatcactt gtcaagatgc gccctctctg
gggagaaggg aacgtgactg gattccctca 1320 ctgttgtatc ttgaataaac
gctgctgctt catcctgtgg gggccgtggc cctgtccctg 1380 tgtgggtggg
gcctcttcca tttccctgac ttagaaacca cagtccacct agaacagggt 1440
ttgagaggct tagtcagcac tgggtagcgt tttgactcca ttctcggctt tcttcttttt
1500 ctttccagga tttttgtgca gaaatggttc ttttgttgcc gtgttagtcc
tccttggaag 1560 gcagctcaga aggcccgtga aatgtcgggg gacaggaccc
ccagggaggg aaccccaggc 1620 tacgcacttt agggttcgtt ctccagggag
ggcgacctga cccccgnatc cgtcggngcg 1680 cgnngnnacn aannnnttcc c 1701
32 771 DNA Homo sapiens misc_feature sequence of STAR32 32
gatcacacag cttgtatgtg ggagctagga ttggaacccc agaagtctgg ccccaggttc
60 atgctctcac ccactgcata caatggcctc tcataaatca atccagtata
aaacattaga 120 atctgcttta aaaccataga attagtagcg taagtaataa
atgcagagac catgcagtga 180 atggcattcc tggaaaaagc ccccagaagg
aattttaaat cagctttcgt ctaatcttga 240 gcagctagtt agcaaatatg
agaatacagt tgttcccaga taatgcttta tgtctgacca 300 tcttaaactg
gcgctgtttt tcaaaaactt aaaaacaaaa tccatgactc ttttaattat 360
aaaagtgata catgtctact tgggaggctg aggtggtggg aggatggctt gagtttgagg
420 ctgcagtatg ctactatcat gcctataaat agccgctgca ttccagcttg
ggcaacatac 480 ccaggcccta tctcaaaaaa ataaaaagta atacatctac
attgaagaaa attaatttta 540 ttgggttttt ttgcattttt attatacaca
gcacacacag cacatatgaa aaaatgggta 600 tgaactcagg cattcaactg
gaagaacagt actaaatcaa tgtccatgta gtcagcgtga 660 ctgaggttgg
tttgtttttt cttttttctt ctcttctctt ctcttttctt tttttttgag 720
acggagcttt gctctttttg cccaggcttg attgcaatgg cgtgatctca g 771 33
1368 DNA Homo sapiens misc_feature sequence of STAR33 33 gcttttatcc
tccattcaca gctagcctgg cccccagagt acccaattct ccctaaaaaa 60
cggtcatgct gtatagatgt gtgtggcttg gtagtgctaa agtggccaca tacagagctc
120 tgacaccaaa cctcaggacc atgttcatgc cttctcactg agttctggct
tgttcgtgac 180 acattatgac attatgatta tgatgacttg tgagagcctc
agtcttctat agcactttta 240 gaatgcttta taaaaaccat ggggatgtca
ttatattcta acctgttagc acttctgttc 300 gtattaccca tcacatccca
acatcaattc tcatatatgc aggtacctct tgtcacgcgc 360 gtccatgtaa
ggagaccaca aaacaggctt tgtttgagca acaaggtttt tatttcacct 420
gggtgcaggt gggctgagtc tgaaaagaga gtcagtgaag ggagacaggg gtgggtccac
480 tttataagat ttgggtaggt agtggaaaat tacaatcaaa gggggttgtt
ctctggctgg 540 ccagggtggg ggtcacaagg tgctcagtgg gagagccttt
gagccaggat gagccagaag 600 gaatttcaca aggtaatgtc atcagttaag
gcagggactg gccattttca cttcttttgt 660 ggtggaatgt catcagttaa
ggcaggaacc ggccattttc acttcttttg tgattcttca 720 cttgcttcag
gccatctgga cgtataggtg caggtcacag tcacagggga taagatggca 780
atggcatagc ttgggctcag aggcctgaca
cctctgagaa actaaagatt ataaaaatga 840 tggtcgcttc tattgcaaat
ctgtgtttat tgtcaagagg cacttatttg tcaattaaga 900 acccagtggt
agaatcgaat gtccgaatgt aaaacaaaat acaaaacctc tgtgtgtgtg 960
tgtgtgtgag tgtgtgtgta tgtgtgtgtg tgtgtattag agaggaaaag cctgtatttg
1020 gaggtgtgat tcttagattc taggttcttt cctgcccacc ccatatgcac
ccaccccaca 1080 aaagaacaaa caacaaatcc caggacatct tagcgcaaca
tttcagtttg catattttac 1140 atatttactt ttcttacata ttaaaaaact
gaaaatttta tgaacacgct aagttagatt 1200 ttaaattaag tttgttttta
cactgaaaat aatttaatat ttgtgaagaa tactaataca 1260 ttggtatatt
tcattttctt aaaattctga acccctcttc ccttatttcc ttttgacccg 1320
attggtgtat tggtcatgtg actcatggat ttgccttaag gcaggagg 1368 34 755
DNA Homo sapiens misc_feature sequence of STAR34 34 actgggcacc
ctcctaggca ggggaatgtg agaactgccg ctgctctggg gctgggcgcc 60
atgtcacagc aggagggagg acggtgttac accacgtggg aaggactcag ggtggtcagc
120 cacaaagctg ctggtgatga ccaggggctt gtgtcttcac tctgcagccc
taacacccag 180 gctgggttcg ctaggctcca tcctgggggt gcagaccctg
agagtgatgc cagtgggagc 240 ctcccgcccc tccccttcct cgaaggccca
ggggtcaaac agtgtagact cagaggcctg 300 agggcacatg tttatttagc
agacaaggtg gggctccatc agcggggtgg cctggggagc 360 agctgcatgg
gtggcactgt ggggagggtc tcccagctcc ctcaatggtg ttcgggctgg 420
tgcggcagct ggcggcaccc tggacagagg tggatatgag ggtgatgggt ggggaaatgg
480 gaggcacccg agatggggac agcagaataa agacagcagc agtgctgggg
ggcaggggga 540 tgagcaaagg caggcccaag acccccagcc cactgcaccc
tggcctccca caagccccct 600 cgcagccgcc cagccacact cactgtgcac
tcagccgtcg atacactggt ctgttaggga 660 gaaagtccgt cagaacaggc
agctgtgtgt gtgtgtgcgt gtatgagtgt gtgtgtgtga 720 tccctgactg
ccaggtcctc tgcactgccc ctggg 755 35 1193 DNA Homo sapiens
misc_feature sequence of STAR35 35 cgacttggtg atgcgggctc ttttttggtt
ccatatgaac tttaaagtag tcttttccaa 60 ttctgtgaag aaagtcattg
gtaggttgat ggggatggca ttgaatctgt aaattacctt 120 gggcagtatg
gccattttca caatgttgat tcttcctatc catgatgatg gaatgttctt 180
ccattagttt gtatcctctt ttatttcctt gagcagtggt ttgtagttct ccttgaagag
240 gtccttcaca tcccttgtaa gttggattcc taggtatttt attctctttg
aagcaaattg 300 tgaatgggag tncactcacg atttggctct ctgtttgtct
gctgggtgta taaanaatgt 360 ngtgatnttn gtacattgat ttngtatccn
tgagacttng ctgaatttgc ttnatcngct 420 tnngggaacc ttttgggctg
aaacnatggg attttctaaa tatacaatca tgtcgtctgc 480 aaacagggaa
caatttgact tcctcttttc ctaattgaat acactttatc tccttctcct 540
gcctaattgc cctgggcaaa acttccaaca ctatgntngn aataggagnt ggtgagagag
600 ggcatccctg ttcttgttgc cagnttttca aagggaatgc ttccagtttt
ggcccattca 660 gtatgatatg ggctgtgggt ngtgtcataa atagctctta
tnattttgaa atgtgtccca 720 tcaataccta atttattgaa agtttttagc
atgaangcat ngttgaattt ggtcaaaggc 780 tttttctgca tctatggaaa
taatcatgtg gtttttgtct ttggctcntg tttatatgct 840 ggatnacatt
tattgatttg tgtatatnga acccagcctn ncatcccagg gatgaagccc 900
acttgatcca agcttggcgc gcngnctagc tcgaggcagg caaaagtatg caaagcatgc
960 atctcaatta gtcagcaccc atagtccgcc cctacctccg cccatccgcc
cctaactcng 1020 nccgttcgcc cattctcgcc catggctgac taatnttttt
annatccaag cggngccgcc 1080 ctgcttganc attcagagtn nagagnnttg
gaggccnagc cttgcaaaac tccggacngn 1140 ttctnnggat tgaccccnnt
taaatatttg gttttttgtn ttttcanngg nga 1193 36 1712 DNA Homo sapiens
misc_feature sequence of STAR36 36 gatcccatcc ttagcctcat cgatacctcc
tgctcacctg tcagtgcctc tggagtgtgt 60 gtctagccca ggcccatccc
ctggaactca ggggactcag gactagtggg catgtacact 120 tggcctcagg
ggactcagga ttagtgagcc ccacatgtac acttggcctc agtggactca 180
ggactagtga gccccacatg tacacttggc ctcaggggac tcaggattag tgagccccca
240 catgtacact tggcctcagg ggactcagga ttagtgagcc ccacatgtac
acttggcctc 300 aggggactca ggactagtga gccccacatg tacacttggc
ctcaggggac tcagaactag 360 tgagccccac atgtacactt ggcttcaggg
gactcaggat tagtgagccc cacatgtaca 420 cttggacacg tgaaccacat
cgatgtgctg cagagctcag ccctctgcag atgaaatgtg 480 gtcatggcat
tccttcacag tggcacccct cgttccctcc ccacctcatc tcccattctt 540
gtctgtcttc agcacctgcc atgtccagcc ggcagattcc accgcagcat cttctgcagc
600 acccccgacc acacacctcc ccagcgcctg cttggccctc cagcccagct
cccgcctttc 660 ttccttgggg aagctccctg gacagacacc ccctcctccc
agccatggct ttttcctgct 720 ctgccccacg cgggaccctg ccctggatgt
gctacaatag acacatcaga tacagtcctt 780 cctcagcagc cggcagaccc
agggtggact gctcggggcc tgcctgtgag gtcacacagg 840 tgtcgttaac
ttgccatctc agcaactagt gaatatgggc agatgctacc ttccttccgg 900
ttccctggtg agaggtactg gtggatgtcc tgtgttgccg gccacctttt gtccctggat
960 gccatttatt tttttccaca aatatttccc aggtctcttc tgtgtgcaag
gtattagggc 1020 tgcagcgggg gccaggccac agatctctgt cctgagaaga
cttggattct agtgcaggag 1080 actgaagtgt atcacaccaa tcagtgtaaa
ttgttaactg ccacaaggag aaaggccagg 1140 aaggagtggg gcatggtggt
gttctagtgt tacaagaaga agccagggag ggcttcctgg 1200 atgaagtggc
atctgacctg ggatctggag gaggagaaaa atgtcccaaa agagcagaga 1260
gcccacccta ggctctgcac caggaggcaa cttgctgggc ttatggaatt cagagggcaa
1320 gtgataagca gaaagtcctt gggggccaca attaggattt ctgtcttcta
aagggcctct 1380 gccctctgct gtgtgacctt gggcaagtta cttcacctct
agtgctttgg ttgcctcatc 1440 tgtaaagtgg tgaggataat gctatcacac
tggttgagaa ttgaagtaat tattgctgca 1500 aagggcttat aagggtgtct
aatactagta ctagtaggta cttcatgtgt cttgacaatt 1560 ttaatcatta
ttattttgtc atcaccgtca ctcttccagg ggactaatgt ccctgctgtt 1620
ctgtccaaat taaacattgt ttatccctgt gggcatctgg cgaggtggct aggaaagcct
1680 ggagctgttt cctgttgacg tgccagacta gt 1712 37 1321 DNA Homo
sapiens misc_feature sequence of STAR37 37 aggatcacat ttaaggaagt
gtgtggggtc cctggatgac accagcaccc agtgcggctc 60 tgtctggcaa
ccgctcccaa ggtggcagga gtgggtgtcc cctgtgtgtc agtgggcagc 120
tcctgctgag cctacagctc actggggagc ctgacagcgg ggccatgtgc ctgacactcc
180 tctctgcttg tggacctggc aaggcaggga gcagaaaaca gagccacttg
aaggctttct 240 gtctgcgtct gtgtgcagtg tggatttagt tgtgcttttt
tcttgctggg agagcacagc 300 caccatttac aagcagtgtc accctcatgg
gtggcgagga cagaacagga gcctctgctc 360 tctgtaccta tctgggcccg
gtgggctccc ttgtcctggc ttccatctct gtctcagcga 420 ccattcagcc
ctgcgcagga acacatgttg cttagaaaag ccaaattcag cccttgtctc 480
tgcctcctct ggtctcatga tgtgcatctg ttaccttgaa actggaaacc agtctatcaa
540 tgtctgtgcc aattttttat tccctcccca acctccttcc ccatacgact
ttttatttat 600 gtaggatgtg tgctgtctaa tgatgggatg accacatttt
tccatgttct aaaagtgctc 660 ctctcccgca gggtcccagg gctggtggtt
gctttgggtc tacagctacg tcttacccgc 720 ctcctgcctc aacagcctgt
gtggtggcaa agccggtgtg gggctgggga acgcagcgtt 780 ctccaggagg
gggacccggc tctccttctg cagtgcaggc gaaggcctag atgccagtgt 840
gacctcccac aaggcgtggc ttccagactc cccggctgga agtgatgctt ttttgcctcc
900 ggccctgggt ttgaagcagc ctggctttct cttggtaagt ggctggtgtc
ttagcagctg 960 caatctgagc tcagccacct acacaccacc gtggccgaca
ctttcattaa aaagtttcct 1020 gagacgactt gcgtgcatgt tgacttcatg
atcagcgccg ctgggaagaa cccctgagcc 1080 ggtggggtgg ggctggaagc
agcaggtgca gtgatggggc tgggtgccca ggaggcctca 1140 gtgctcaatc
aggccaaggt ggccaagccc aggctgcagg gaaggccggc ctgggggttg 1200
tgggtgagca caggcaggca ccagctgggc agtgttagga tgctggagca gcatccgtaa
1260 ccccactgag tggggtagtc tggttggggc agggaccgct gttgctttgg
cagagagaga 1320 t 1321 38 1445 DNA Homo sapiens misc_feature
sequence of STAR38 38 gatctatggg agtagcttcc ttagtgagct ttcccttcaa
atactttgca accaggtaga 60 gaattttgga gtgaaggttt tgttcttcgt
ttcttcacaa tatggatatg catcttcttt 120 tgaaaatgtt aaagtaaatt
acctctcttt tcagatactg tcttcatgcg aacttggtat 180 cctgtttcca
tcccagcctt ctataaccca gtaacatctt ttttgaaacc agtgggtgag 240
aaagacacct ggtcaggaac gcggaccaca ggacaactca ggctcaccca cggcatcaga
300 ctaaaggcaa acaaggactc tgtataaagt accggtggca tgtgtatnag
tggagatgca 360 gcctgtgctc tgcagacagg gagtcacaca gacacttttc
tataatttct taagtgcttt 420 gaatgttcaa gtagaaagtc taacattaaa
tttgattgaa caattgtata ttcatggaat 480 attttggaac ggaataccaa
aaaatggcaa tagtggttct ttctggatgg aagacaaact 540 tttcttgttt
aaaataaatt ttattttata tatttgaggt tgaccacatg accttaagga 600
tacatataga cagtaaactg gttactacag tgaagcaaat taacatatct accatcgtac
660 atagttacat ttttttgtgt gacaggaaca gctaaaatct acgtatttaa
caaaaatcct 720 aaagacaata catttttatt aactatagcc ctcatgatgt
acattagatc gtgtggttgt 780 ttcttccgtc cccgccacgc cttcctcctg
ggatggggat tcattcccta gcaggtgtcg 840 gagaactggc gcccttgcag
ggtaggtgcc ccggagcctg aggcgggnac tttaanatca 900 gacgcttggg
ggccggctgg gaaaaactgg cggaaaatat tataactgna ctctcaatgc 960
cagctgttgt agaagctcct gggacaagcc gtggaagtcc cctcaggagg cttccgcgat
1020 gtcctaggtg gctgctccgc ccgccacggt catttccatt gactcacacg
cgccgcctgg 1080 aggaggaggc tgcgctggac acgccggtgg cgcctttgcc
tgggggagcg cagcctggag 1140 ctctggcggc agcgctggga gcggggcctc
ggaggctggg cctggggacc caaggttggg 1200 cggggcgcag gaggtgggct
cagggttctc cagagaatcc ccatgagctg acccgcaggg 1260 cggccgggcc
agtaggcacc gggcccccgc ggtgacctgc ggacccgaag ctggagcagc 1320
cactgcaaat gctgcgctga ccccaaatgc tgtgtccttt aaatgtttta attaagaata
1380 attaataggt ccgggtgtgg aggctcaagc cttaatcccc agcacctggc
gaggccgagg 1440 aggga 1445 39 2331 DNA Homo sapiens misc_feature
sequence of STAR39 39 gtgaaataga tcactaaagc tgattcctct tgtctaaatg
aaactttcta ccctttgatg 60 gacagctatg ctttccccat cctctcccgt
cccccagccc ttggtaacca tcatcctact 120 ctctacttgt aggagttcaa
cttgtttaga ttttgtgagt gagaacatgt ggtatttgcc 180 tttagagtcc
tctaggttta tccatattgt gttaaatgac aggattccct gcctttttaa 240
ggctgaatag tatttcattg taatatatat acatacacac acacatatac acacacatat
300 atatacatat atacatatat gtacatagat acatatatat gtacatatat
acacacacat 360 atacacacat atatacacat atatacatat acatatatac
acatatatgt acatatatat 420 aacttttttt catttatcca ttcacttaat
acatatgatg gagggcttta tatatgccag 480 gctctgtgat gaatgctgga
aattcaatag tgagaaagac tcagtctctg cctccaaaga 540 gcatcatggg
ctaggtgctg caacgaggaa ttgccaactg ttgtcatgag agcacagaga 600
agggactcaa ccagccttga agaatcaggg gaggcttcta agctaatggt gtgtgcctgg
660 ggatcacatt gtttcaagca gcagtaacag gatgtgctca ggtccagatg
tgagagagag 720 agagagcata tgtcttcaag aaactaacag tagctcccta
tagctgaagc aggagtacaa 780 aatagtgagt ttaagtgatg aggcaagaga
tatgaagaag cttgaccatg cagctacacc 840 gggcagcatg ccctctgaga
catctcatgg aagccggaaa tgggagtgcc ttgataccaa 900 gccagagaaa
ttataatact aagtagatag actgagcagc actcctcctg ggaagaatga 960
gacaagccct gaatttggag gtaagttgtg gattggtgat tagaggagag gtaacaggca
1020 ccaaagcaag aaatagtatt gatgcaaagc tgaggttaat tggatgacaa
aatgaagagc 1080 ataaggggct cagacacaga ctgagcagaa aacgagtagc
atctgaacct agattgagtt 1140 actaatggat gagaaagagt tcttaaagtt
gatgaccacg ggatccatat ataagaatgt 1200 ccaatctccc caaattgatc
cacgagttca gtgcaatgcc aatcaaaatc ccactaacaa 1260 gtttatttta
aaatgtaaat gaaaatacaa aatttttaaa aagcaaagca atattgaaaa 1320
cccaggaaaa attaggagga cttacacaac ctgatctcaa aacttaccat tatcaagaca
1380 gagtgttatt gacacaagga gagacaaata gataaacgga atgtggtagt
ctggagatgc 1440 acccacatgt atgtggtcaa ttgatttttg gccaaggcac
caagtcaatt caaaggagca 1500 aggaaagtag tacagaaaca accaaatatt
gttttggaaa ataatgacaa agggcttata 1560 accagaatat aagcatataa
atataattct ttcaaatcaa taataagaag gcaaatatct 1620 aataaaaatg
agcaaagact tgaaaagtca cttaaaaagg cttattaatt agaaatatgc 1680
aaatgttatt agtcttcagt ggaatttaca ttaaaccaca agggatacta ttatatctta
1740 tgcccactag aataaccaaa ggaaaaaaga cagacaaaac aaaatgctgg
tgaggatgtg 1800 aagcaactgg aactctcata cattattggt ggtaatgtaa
aatttataca accattatga 1860 ataaaggttt ggcagtttct tacaaagttg
aatgcacttc tccacgatga ctaggctttt 1920 cactcatagg cgtctggctc
cctagaactg aaaacatatg ttcacaagaa gacttgcaaa 1980 tatatattct
cccacgtcag gagatatttg ctatgcattt aactgacata agattagtgc 2040
tagagtttat aatgaggttc ttcaaatcta aaagaaaatg caaagcatat aatagtaagg
2100 ggtgcaggcc aggcgcagtg gctcactctg taatcccagc actttgggag
gccgaggtgg 2160 gcggatcaca aggtcaggag ttcgagacca acctggccaa
catagtgaaa ccctgtctct 2220 actaaaaata caaaaactag ccaggtgcgg
tgtcatgcac ctgtagtccc agctactcgg 2280 gaggccgagg caggagaatc
acttgaacct gggaggtgga ggttgcagtg a 2331 40 1071 DNA Homo sapiens
misc_feature sequence of STAR40 40 gctgtgattc aaactgtcag cgagataagg
cagcagatca agaaagcact ccgggctcca 60 gaaggagcct tccaggccag
ctttgagcat aagctgctga tgagcagtga gtgtcttgag 120 tagtgttcag
ggcagcatgt taccattcat gcttgacttc tagccagtgt gacgagaggc 180
tggagtcagg tctctagaga gttgagcagc tccagcctta gatctcccag tcttatgcgg
240 tgtgcccatt cgctttgtgt ctgcagtccc ctggccacac ccagtaacag
ttctgggatc 300 tatgggagta gcttccttag tgagctttcc cttcaaatac
tttgcaacca ggtagagaat 360 tttggagtga aggttttgtt cttcgtttct
tcacaatatg gatatgcatc ttcttttgaa 420 aatgttaaag taaattacct
ctcttttcag atactgtctt catgcgaact tggtatcctg 480 tttccatccc
agccttctat aacccagtaa catctttttt gaaaccagtg ggtgagaaag 540
acacctggtc aggaacgcgg accacaggac aactcaggct cacccacggc atcagactaa
600 aggcaaacaa ggactctgta taaagtaccg gtggcatgtg tattagtgga
gatgcagcct 660 gtgctctgca gacagggagt cacacagaca cttttctata
atttcttaag tgctttgaat 720 gttcaagtag aaagtctaac attaaatttg
attgaacaat tgtatattca tggaatattt 780 tggaacggaa taccaaaaaa
tggcaatagt ggttctttct ggatggaaga caaacttttc 840 ttgtttaaaa
taaattttat tttatatatt tgaggttgac cacatgacct taaggataca 900
tatagacagt aaactggtta ctacagtgaa gcaaattaac atatctacca tcgtacatag
960 ttacattttt ttgtgtgaca ggaacagcta aaatctacgt atttaacaaa
aatcctaaag 1020 acaatacatt tttattaact atagccctca tgatgtacat
tagatctcta a 1071 41 1135 DNA Homo sapiens misc_feature sequence of
STAR41 41 cgtgtgcagt ccacggagag tgtgttctcc tcatcctcgt tccggtggtt
gtggcgggaa 60 acgtggcgct gcaggacacc aacatcagtc acgtatttca
ttctggaaaa aaaagtagca 120 caagcctcgg ctggttccct ccagctctta
ccaggcagcc taagcctagg ctccattccc 180 gctcaaggcc ttcctcaggg
gcctgctcac cacaggagct gttcccatgc agggactaag 240 gacatgcagc
ctgcatagaa accaagcacc caggaaaaca tgattggatg gagcgggggg 300
gtgtggtctc tagccttgtc cacctccggt cctcatgggt ctcacacctc ctgagaatgg
360 gcaccgcaga ggccacagcc catacagcca agatgacaga ctccgtaagt
gacagggatc 420 cacagcagag tgggtgaaat gttccctata aactttacaa
aattaatgag ggcaggggga 480 ggggagaaat gaaaatgaac ccagctcgca
gcacatcagc atcagtcact aggtcggcgt 540 gctctctgac tgcttcctcg
tagctgcttg gtgtctcatt gcctcagaag catgtagacc 600 ctgtcacaag
attgtagttc ccctaactgc tccgtagatc acaacttgaa ccttaggaaa 660
tgctgttttc cctttgagat attcctttgg gtcctgtata ctgatggagc tactgactga
720 gctgctccga aggaccccac gaggagctga ctaaaccaag agtgcagttt
gtacaccctg 780 atgattacat cccccttgcc ccaccaatca actctcccaa
ttttccagcc cctcaccctc 840 cagtcccctt aaaagcccca gcccaggccg
ggcacagtgg ctcatgcctg taatcccagc 900 actttgggag gccaaggtgg
gcagatcacc tgagggcagg aatttgagac cagcctgacc 960 aacatgaaga
aaccccgtct ctattacaaa tacaaaatta gccgggcgtg ttgctgcata 1020
ctggtaatcc cagctacttg ggagggtgag gcaggagaat cacttgaatc tgggaggcgg
1080 aggttgcgat gagccgagac agcgccattg cactgcagcc tgggcaacaa gagca
1135 42 735 DNA Homo sapiens misc_feature sequence of STAR42 42
aagggtgaga tcactaggga gggaggaagg agctataaaa gaaagaggtc actcatcaca
60 tcttacacac tttttaaaac cttggttttt taatgtccgt gttcctcatt
agcagtaagc 120 cctgtggaag caggagtctt tctcattgac caccatgaca
agaccctatt tatgaaacat 180 aatagacaca caaatgttta tcggatattt
attgaaatat aggaattttt cccctcacac 240 ctcatgacca cattctggta
cattgtatga atgaatatac cataatttta cctatggctg 300 tatatttagg
tcttttcgtg caggctataa aaatatgtat gggccggtca cagtgactta 360
cgcccgtagt cccagaactt tgggaggccg aggcgggtgg atcacctgag gtcgggagtt
420 caaaaccagc ctgaccaaca tggagaaacc ccgtctctgc taaaaataca
aaaattaact 480 ggacacggtg gcgtatgcct gtaatcccag ctactcggga
agctgaggca ggagaactgc 540 ttgaacccag gaggcggagg ttgtggtgag
tcgagattgc gccattgcac tccagcctgg 600 gcaacaagag cgaaattcca
tctcaaaaaa aagaaaaaag tatgactgta tttagagtag 660 tatgtggatt
tgaaaaatta ataagtgttg ccaacttacc ttagggttta taccatttat 720
gagggtgtcg gtttc 735 43 1227 DNA Homo sapiens misc_feature sequence
of STAR43 43 caaatagatc tacacaaaac aagataatgt ctgcccattt ttccaaagat
aatgtggtga 60 agtgggtaga gagaaatgca tccattctcc ccacccaacc
tctgctaaat tgtccatgtc 120 acagtactga gaccaggggg cttattccca
gcgggcagaa tgtgcaccaa gcacctcttg 180 tctcaatttg cagtctaggc
cctgctattt gatggtgtga aggcttgcac ctggcatgga 240 aggtccgttt
tgtacttctt gctttagcag ttcaaagagc agggagagct gcgagggcct 300
ctgcagcttc agatggatgt ggtcagcttg ttggaggcgc cttctgtggt ccattatctc
360 cagcccccct gcggtgttgc tgtttgcttg gcttgtctgg ctctccatgc
cttgttggct 420 ccaaaatgtc atcatgctgc accccaggaa gaatgtgcag
gcccatctct tttatgtgct 480 ttgggctatt ttgattcccc gttgggtata
ttccctaggt aagacccaga agacacagga 540 ggtagttgct ttgggagagt
ttggacctat gggtatgagg taatagacac agtatcttct 600 ctttcatttg
gtgagactgt tagctctggc cgcggactga attccacaca gctcacttgg 660
gaaaacttta ttccaaaaca tagtcacatt gaacattgtg gagaatgagg gacagagaag
720 aggccctaga tttgtacatc tgggtgttat gtctataaat agaatgcttt
ggtggtcaac 780 tagacttgtt catgttgaca tttagtcttg ccttttcggt
ggtgatttaa aaattatgta 840 tatcttgttt ggaatatagt ggagctatgg
tgtggcattt tcatctggct ttttgtttag 900 ctcagcccgt cctgttatgg
gcagccttga agctcagtag ctaatgaaga ggtatcctca 960 ctccctccag
agagcggtcc cctcacggct cattgagagt ttgtcagcac cttgaaatga 1020
gtttaaactt gtttattttt aaaacattct tggttatgaa tgtgcctata ttgaattact
1080 gaacaacctt atggttgtga agaattgatt tggtgctaag gtgtataaat
ttcaggacca 1140 gtgtctctga agagttcatt tagcatgaag tcagcctgtg
gcaggttggg tggagccagg 1200 gaacaatgga gaagctttca tgggtgg 1227 44
1586 DNA Homo sapiens misc_feature sequence of STAR44 44 cacctgcctc
agcctcccaa agtgctgaga ttcaaagaaa ttttcatgga gaggggacag 60
atggagtcaa ttcttgtggg gtgaacatga gtaccacagt tagactgagg ttgggaaaga
120 ttttccagac aattggaaga gcatgtgaaa gacacagatt ttgagaaatg
ttaagtctag 180 ggaactgcaa ggcttttggc acaagaaagc cactgtagac
tatagaggca ggatgcctag 240 attcaaatcc caactgctac acttctaagc
tttgtaattt tggcaagttt ttaccctcta 300 ttttcttatc tataaaatat
agattttata tatatagata tagatatata gatagataat 360 aattgtgcat
gcctaataaa gttgtcaaag attaaatgtt atatgtgaag tattttgtac 420
ggtgatagga acccaggaag ggctctatga atattatgta ttattattat tctaaagtag
480 ctggaataca atgttcaaag gagatagtgg caggagataa gtttgaattg
aaagattgag 540 gccagaacat aaagtgcctc ctatattata ttttacataa
ttggaacatc attgaaaaat 600 ttaagtatta tttatgtgtg tatgtgtgtt
ttatataatt aattctagtt catcatttta 660 aaatatcttt ctgatgtcac
tgtgaacaac agatgagaag aagtgaatcc tgagttaagg 720 agaccagctc
tctgattact gccataatcc agggagggta ccataaggat ttcaactgga 780
agtgaatcca tcatgatgga gaggaaggac agggctgaaa aatacttagg aagtagtatc
840 agtaggactg gttaagagag agcagaggca ggctacaggg gttggaggtg
tcaatcacag 900 agatagggaa aatgggagga gaagcaggct ttgaaaaagt
ggcttgtctt gtaaaattat 960 gtgctgttaa aacagtacaa gaaattaata
tattcaatcc caaaatacag ggacaattct 1020 ttttgaaaga gttacccaga
tagtcttcct tgaagttttc agttaaagaa atttcttgtt 1080 aacaaataat
gtagtcatag aagaaaacac ttaaaacttt attgaataaa gctaataaat 1140
catttaatat aatttatagg aaattgttac ataacacaca cattcaatac tttttgctaa
1200 agtataaatt aatggaagga gagcacgcac acagaggttg aattatgttt
atgactttat 1260 tagtcaagaa tacaaaattg agtagctaca tcaagcagaa
gcacatgctt tacaatccag 1320 cacagaatcc cttgacatcc aaactcccga
aacagacatg taaatacaga tgacattgtc 1380 agaacaaaat agggtctcac
ccgacctata atgttctttt cttgatataa atatgcacat 1440 gaattgcata
cggtcatatg gttccaatta ccattatttc ctctgggctt agctatccat 1500
ctaaggggaa tttacaccaa cactgtactt ctacttgcaa gaatatatga aagcatagtt
1560 aacttctggc ttaggacccc aactca 1586 45 1981 DNA Homo sapiens
misc_feature sequence of STAR45 45 atggatcata gggtaaataa atttataatt
tcttgagaaa gcttcgtact gttttccaag 60 atggctgtac taatttccat
tcctaccaac agtgtacagg gtttcttttt ctccacatcc 120 tcaccaacac
ttatcttcca tcttttttta taatagccct agtaaaatgt gtgaggtgat 180
atctcattgt ggcattgatt tgcacttctc tgataattag gaatgtttat gattttttca
240 tgtacctggt tggccttttg tatgatgtag gaaatgtcta ttctgattct
ttgcttattt 300 tttaataagc atagtttttt tcttattttt gagtaggttg
agttgcttat atattattat 360 atgagcccct tacctgatgt atggtttaaa
aatattatcc catttgtggg ttctcttaat 420 tctatcattg cttcttttcc
tgtggaaaag ttttaagttt tatgcagtct catttgtgtg 480 ttttgctttt
gttgcctttt ggaataatct acagaaaatc atagctcagg ccaatgtcat 540
acagtctcct tctatatttc cttgtagtag ttttacattt aaactttaat tttgatttga
600 tgcttgtata aagagcaaaa taaaagtcaa attttattct tctgtatgtg
gatagtcagt 660 tttgtctaca ccatttattg aaaataattt tctttcttca
ctgtgtattt ttagttattt 720 tatcaaaaaa tcaattgacc acagacacac
ggatttattt acaggttcta tatccctttg 780 tactgtttta catgtctgtt
tttatgccat tgctatgctg ttttaattcc tatagctttg 840 taatagagtt
tggagtcagg tagtctgatg cctccagctt tgttcttttt gttcaagatt 900
gctttggttg gtccaggtct tttgtggttc catacaaatt ttagcagtaa tttttctatt
960 tctgtgaaga atgacattgg aatttgatag tggttgcatt taatctgtag
attgctttgg 1020 gtagcattga cacttttaca atactaattt ttgaatccat
caatgaagga tgtttctcca 1080 tttatttatg ccattttaat ttttttcatc
aatgtgctat agttttcagt atgtaaatct 1140 tttatggttt tgattaaatt
tactcctgtc ttttatatat ttatatatct gttttgattc 1200 tattataaat
tgaattgcct ttatttttca ggtaatagtt tgtcattagt taatagaaac 1260
aataatgata tttgtatgtt gattttgtaa ctattaactt tattgaattt cttcatcagc
1320 tataaccatt tattttggtg gaatctttaa gattttctct atcttaagat
tatattttca 1380 aaaaacagaa acaatcttac ctcttccttc cctatgtgga
tttcttttac gtctttgtct 1440 tgtgtaactg ttctggctag gcaattacac
ataatgtttt catcatttat aattttacat 1500 cacatccatc tattgtggca
cattgattgc tacttttcaa gttgtaaacc tggacattta 1560 tcactactct
tcctccaata caggagtcca tggcgtggtg tgggccctac tgtgccacag 1620
tccagggcac ggctgggctg aggttctctt gtgcaagagt ccgtggctct gcggagcaag
1680 agttctccag tgccttagtc cagggttagg caggggtggg gctccttcag
tagcttagtc 1740 cagtgcgccg ccctgcgagg gtcctcctga gcaggagtac
acgatgaggc agggtcctac 1800 tgtgccttag cccaggaagc ggggggctgg
gtcctctggt gccatagtcc aggctgccgg 1860 gagctgggtc ctctggtgcc
atagctcagg ccggcgggag ctgggtcctc tggtgccgta 1920 gtccagggtg
cagcagaaca ggagtcctgc ggagcagtag tccagggcac gctggggcgt 1980 g 1981
46 1859 DNA Homo sapiens misc_feature sequence of STAR46 46
attgtttttc tcgcccttct gcattttctg caaattctgt tgaatcattg cagttactta
60 ggtttgcttc gtctccccca ttacaaacta cttactgggt ttttcaaccc
tagttccctc 120 atttttatga tttatgctca tttctttgta cacttcgtct
tgctccatct cccaactcat 180 ggcccctggc tttggattat tgttttggtc
ttttattttt tgtcttcttc tacctcaaca 240 cttatcttcc tctcccagtc
tccggtaccc tatcaccaag gttgtcatta acctttcata 300 ttattcctca
ttatccatgt attcatttgc aaataagcgt atattaacaa aatcacaggt 360
ttatggagat ataattcaca taccttaaaa ttcaggcttt taaagtgtac ctttcatgtg
420 gtttttggta tattcacaaa gttatgcatt gatcaccacc atctgattcc
ataacatgtt 480 caatacctca aaaagaagtc tgtactcatt agtagtcatt
tcacattcac cactccctct 540 ggctctgggc agtcactgat ctttgtgtct
ctatggattt gcctagtcta ggtattttta 600 tgtaaatggc atcatacaac
atgtgacctt ttgtttggct tttttcattt agcaaaatgt 660 tatcaaggtc
tgtccctgtt gtagcatgta ttagcacttc atttcttata tgctgaatga 720
tatactttat ttgtccatca gttgttcatg ctttatttgt ccatcagttg atgaacattt
780 gcgtttttgc cactttgggc tattaagaat aatgctactg tgaacaagtg
tgtacaagtt 840 cctctacaaa tttttgtgtg gacatatcct ttcagttctc
tcaggtgtat atctgggaat 900 tgaattgctg ggtcgtgtag tagctatgtt
aaacactttg agaaactgct ataatgttct 960 ccagagctgt accattttaa
attctgtgta tgaggattcc acgttctcca cttcctcacc 1020 agtgtatgga
tttgggggta tactttttaa aaagtgggat taggctgggc acagtggctc 1080
acacctgtaa tcccaacact tcaggaagct gaggtgggag gatcacttga gcctagtagt
1140 ttgagaccag cctgggcaac atagggagac cctgtctcta caaaaaataa
tttaaaataa 1200 attagctggg cgttgtggca cacacctgta gtcccagcta
catgggaggc tgaggtggaa 1260 ggattccctg agcccagaag tttgaggttg
cagtgagcca tgatggcagc actatactgt 1320 agcctgggtg tcagagcaag
actccgtttc agggaagaaa aaaaaaagtg ggatgatatt 1380 tttgacactt
ttcttcttgt tttcttaatt tcatacttct ggaaattcca ttaaattagc 1440
tggtaccact ctaactcatt gtgtttcatg gctgcatagt aatattgcat aatataaata
1500 taccattcat tcatcaaagt tagcagatat tgactgttag gtgccaggca
ctgctctaag 1560 cgttaaagaa aaacacacaa aaacttttgc attcttagag
tttattttcc aatggagggg 1620 gtggagggag gtaagaattt aggaaataaa
ttaattacat atatagcata gggtttcacc 1680 agtgagtgca gcttgaatcg
ttggcagctt tcttagtagt ataaatacag tactaaagat 1740 gaaattactc
taaatggtgt tacttaaatt actggaatag gtattactat tagtcacttt 1800
gcaggtgaaa gtggaaacac catcgtaaaa tgtaaaatag gaaacagctg gttaatgtt
1859 47 1082 DNA Homo sapiens misc_feature sequence of STAR47 47
atcattagtc attagggaaa tgcaaatgaa aaacacaagc agccaccaat atacacctac
60 taggatgatt taaaggaaaa taagtgtgaa gaaggacgta aagaaattgt
aaccctgata 120 cattgatggt agaaatggat aaagttgcag ccactgtgaa
aaacagtctg cagtggctca 180 gaaggttaaa tatagaaccc ctgttggacc
caggaactct actcttaggc accccaaaga 240 atagagaaca gaaatcaaac
agatgtttgt atactaatgt ttgtagcatc acttttcaca 300 ggagccaaaa
ggtggaaata atccaaccat cagtgaacaa atgaatgtaa taaaagcaag 360
gtggtctgca tgcaatgcta catcatccat ctgtaaaaaa cgaacatcat tttgatagat
420 gatacaacat gggtggacat tgagaacatt atgcttagtg aaataagcca
gacacaaaag 480 gaatatattg tataattgta attacatgaa gtgcctagaa
tagtcaaatt catacaagag 540 aaagtgggat aggaatcacc atgggctgga
aataggggga aggtgctata ctgcttattg 600 tggacaaggt ttcgtaagaa
atcatcaaaa ttgtgggtgt agatagtggt gttggttatg 660 caaccctgtg
aatatattga atgccatgga gtgcacactt tggttaaaag gttcaaatga 720
taaatattgt gttatatata tttccccacg atagaaaaca cgcacagcca agcccacatg
780 ccagtcttgt tagctgcctt cctttacctt caagagtggg ctgaagcttg
tccaatcttt 840 caaggttgct gaagactgta tgatggaagt catctgcatt
gggaaagaaa ttaatggaga 900 gaggagaaaa cttgagaatc cacactactc
accctgcagg gccaagaact ctgtctccca 960 tgctttgctg tcctgtctca
gtatttcctg tgaccacctc ctttttcaac tgaagacttt 1020 gtacctgaag
gggttcccag gtttttcacc tcggcccttg tcaggactga tcctctcaac 1080 ta 1082
48 1242 DNA Homo sapiens misc_feature sequence of STAR48 48
atcatgtatt tgttttctga attaattctt agatacatta atgttttatg ttaccatgaa
60 tgtgatatta taatataata tttttaattg gttgctactg tttataagaa
tttcattttc 120 tgtttacttt gccttcatat ctgaaaacct tgctgatttg
attagtgcat ccacaaattt 180 tcttggattt tctatgggta attacaaatc
tccacacaat gaggttgcag tgagccaaga 240 tcacaccact gtactccagc
ctgggcgaca gagtgagaca ccatctcaca aaaacacata 300 aacaaacaaa
cagaaactcc acacaatgac aacgtatgtg ctttcttttt ttcttcctct 360
ttctataata tttctttgtc ctatcttaac tgaactggcc agaaacccca ggacaatgat
420 aaatacgagc agtgtcaaca gacatctcat tccctttcct agcttttata
aaaataacga 480 ttatgcttca acattacata tggtggtgtc gatggttttg
ttatagataa gcttatcagg 540 ttaagaaatt tgtctgcgtt tcctagtttg
gtataaagat tttaatataa atgaatgttg 600 tattttatca tcttattttt
ttcctacatc tgctaaggta atcctgtgtt ttcccctttt 660 caatctccta
atgtggtgaa tgacattaaa ataccttcta ttgttaaaat attcttgcaa 720
cgctgtatag aaccaatgcc tttattctgt attgctgatg gatttttgaa aaatatgtag
780 gtggacttag ttttctaagg ggaatagaat ttctaatata tttaaaatat
tttgcatgta 840 tgttctgaag gacattggtg tgtcatttct ataccatctg
gctactagag gagccgactg 900 aaagtcacac tgccggagga ggggagaggt
gctcttccgt ttctggtgtc tgtagccatc 960 tccagtggta gctgcagtga
taataatgct gcagtgccga cagttctgga aggagcaaca 1020 acagtgattt
cagcagcagc agtattgcgg gatccccacg atggagcaag ggaaataatt 1080
ctggaagcaa tgacaatatc agctgtggct atagcagctg agatgtgagt tctcacggtg
1140 gcagcttcaa ggacagtagt gatggtccaa tggcgcccag acctagaaat
gcacatttcc 1200 tcagcaccgg ctccagatgc tgagcttgga cagctgacgc ct 1242
49 1015 DNA Homo sapiens misc_feature sequence of STAR49 49
aaaccagaaa cccaaaacaa tgggagtgac atgctaaaac cagaaaccca aaacaatggg
60 agggtcctgc taaaccagaa acccaaaaca atgggagtga agtgctaaaa
ccagaaaccc 120 aaaacaatgg gagtgtcctg ctacaccaga aacccaaaac
gatgggagtg acgtgataaa 180 accagacacc caaaacaatg ggagtgacgt
gctaaaccag aaacccaaaa caatgggagt 240 gacgtgctaa aacctggaaa
cctaaaacaa tgcgagtgag gtgctaacac cagaatccat 300 aacaatgtga
gtgacgtgct aaaccagaac ccaaaacaat gggagtgacg tgctaaaaca 360
ggaacccaaa acaatgagag tgacgtgcta aaccagaaac ccaaaacaat gggaatgacg
420 tgctaaaacc ggaacccaaa acaatgggag tgatgtgcta aaccagaaac
ccaaaacaat 480 gggaatgaca tgctaaaact ggaacccaaa acaatggtaa
ctaagagtga tgctaaggcc 540 ctacattttg gtcacactct caactaagtg
agaacttgac tgaaaaggag gatttttttt 600 tctaagacag agttttggtc
tgtcccccag agtggagtgc agtggcatga tctcggctca 660 ctgcaagctc
tgcctcccgg gttcaggcca ttctcctgcc tcagcctcct gagtagctgg 720
gaatacaggc acccgccacc acacttggct aattttttgt atttttagta gagatggggt
780 ttcaccatat tagcaaggat ggtctcaatc tcctgacctc gtgatctgcc
cacctcaggc 840 tcccaaagtg ctgggattac aggtgtgagc caccacaccc
agcaaaaagg aggaattttt 900 aaagcaaaat tatgggaggc cattgttttg
aactaagctc atgcaatagg tcccaacaga 960 ccaaaccaaa ccaaaccaaa
atggagtcac tcatgctaaa tgtagcataa tcaaa 1015 50 2355 DNA Homo
sapiens misc_feature sequence of STAR50 50 caaccatcgt tccgcaagag
cggcttgttt attaaacatg aaatgaggga aaagcctagt 60 agctccattg
gattgggaag aatggcaaag agagacaggc gtcattttct agaaagcaat 120
cttcacacct gttggtcctc acccattgaa tgtcctcacc caatctccaa cacagaaatg
180 agtgactgtg tgtgcacatg cgtgtgcatg tgtgaaagta tgagtgtgaa
tgtgtctata 240 tgggaacata tatgtgattg tatgtgtgta actatgtgtg
actggcagcg tggggagtgc 300 tggttggagt gtggtgtgat gtgagtatgc
atgagtggct gtgtgtatga ctgtggcggg 360 aggcggaagg ggagaagcag
caggctcagg tgtcgccaga gaggctggga ggaaactata 420 aacctgggca
atttcctcct catcagcgag cctttcttgg gcaatagggg cagagctcaa 480
agttcacaga gatagtgcct gggaggcatg aggcaaggcg gaagtactgc gaggaggggc
540 agagggtctg acacttgagg ggttctaatg ggaaaggaaa gacccacact
gaattccact 600 tagccccaga ccctgggccc agcggtgccg gcttccaacc
ataccaacca tttccaagtg 660 ttgccggcag aagttaacct ctcttagcct
cagtttcccc acctgtaaaa tggcagaagt 720 aaccaagctt accttcccgg
cagtgtgtga ggatgaaaag agctatgtac gtgatgcact 780 tagaagaagg
tctagggtgt gagtggtact cgtctggtgg gtgtggagaa gacattctag 840
gcaatgagga ctggggagag cctggcccat ggcttccact cagcaaggtc agtctcttgt
900 cctctgcact cccagccttc cagagaggac cttcccaacc agcactcccc
acgctgccag 960 tcacacatag ttacacacat acaatcacat atatgttccc
atatagacac attcacactc 1020 ataccttcac acatgcacac gcatgtgcac
acacagtcac tcatttctgt gttggagatt 1080 gggtgaggac attcaatggg
tgaggaccaa caggtgtgaa gattgctttc tagaaaatga 1140 ctcctgtctc
tctttgccat tcttcccaat ccgatggagc tactaggctt ttccctcatt 1200
tcatgtttaa taaaccttcc caatggcgaa atgggctttc tcaagaagtg gtgagtgtcc
1260 catccctgcg gtggggacag gggtggcagc ggacaagcct gcctggaggg
aactgtcagg 1320 ctgattccca gtccaactcc agcttccaac acctcatcct
ccaggcagtc ttcattcttg 1380 gctctaattt cgctcttgtt ttctttttta
tttttatcga gaactgggtg gagagctttt 1440 ggtgtcattg gggattgctt
tgaaaccctt ctctgcctca cactgggagc tggcttgagt 1500 caactggtct
ccatggaatt tcttttttta gtgtgtaaac agctaagttt taggcagctg 1560
ttgtgccgtc cagggtggaa agcagcctgt tgatgtggaa ctgcttggct cagatttctt
1620 gggcaaacag atgccgtgtc tctcaactca ccaattaaga agcccagaaa
atgtggcttg 1680 gagaccacat gtctggttat gtctagtaat tcagatggct
tcacctggga agccctttct 1740 gaatgtcaaa gccatgagat aaaggacata
tatatagtag ctagggtggt ccacttctta 1800 ggggccatct ccggaggtgg
tgagcactaa gtgccaggaa gagaggaaac tctgttttgg 1860 agccaaagca
taaaaaaacc ttagccacaa accactgaac atttgttttg tgcaggttct 1920
gagtccaggg agggcttctg aggagagggg cagctggagc tggtaggagt tatgtgagat
1980 ggagcaaggg ccctttaaga ggtgggagca gcatgagcaa aggcagagag
gtggtaatgt 2040 ataaggtatg tcatgggaaa gagtttggct ggaacagagt
ttacagaata gaaaaattca 2100 acactattaa ttgagcctct actacgtgct
cgacattgtt ctagtcactg agataggttt 2160 ggtatacaaa acaaaatcca
tcctctatgg acattttagt gactaacaac aatataaata 2220 ataaaagtga
acaaaagctc aaaacatgcc aggcactatt atttatttat ttatttattt 2280
atttatttat tttttgaaac agagtctcgc tctgttgccc aggctggagt gtagtggtgc
2340 gatctcggct cactg 2355 51 2289 DNA Homo sapiens misc_feature
sequence of STAR51 51 tcacaggtga caccaatccc ctgaccacgc tttgagaagc
actgtactag attgactttc 60 taatgtcagt cttcattttc tagctctgtt
acagccatgg tctccatatt atctagtaca 120 acacacatac aaatatgtgt
gatacagtat gaatataata taaaaatatg tgttataata 180 taaatataat
attaaaatat gtctttatac tagataataa tacttaataa cgttgagtgt 240
ttaactgctc taagcacttt acctgcagga aacagttttt tttttatttt ggtgaaatac
300 aactaacata aatttattta caattttaag catttttaag tgtatagttt
agtggagtta 360 atatattcaa aatgttgtgc agccgtcacc atcatcagtc
ttcataactc ttttcatatt 420 gtaaaattaa aagtttatgc tcatttaaaa
atgactccca atttcccccc tcctcaacct 480 ctggaaacta ccattctatt
ttctgcctcc gtagttttgc ccactctaag tacctcacat 540 aagtggaatt
tgtcttattt gcctgtttgt gaccggctga tttcatttag tataatgtcc 600
tcaagtttta ttcacgttat atagcatatg tcataatttt cttcactttt aagcttgagt
660 aatatttcat cgtatgtatc tcacattttg cttatccatt catctctcag
tggacacttg 720 agttgcttct acattttagc tgttgtgaat actgctgcta
tgaacatggg tgtataaata 780 tctcaagacc tttttatcag ttttttaaaa
tatatactca gtagtagttt agctggatta 840 tatggtaatt ttatttttaa
tttttgagga actgtcctac ccttttattc aatagtagct 900 ataccaattg
acaattggca ttcctaccaa cagggcataa gggttctcaa ttctccacat 960
attccctgat acttgttatt ttcaggtgtt tttttttttt tttttttttt atgggagcca
1020 tgttaatggg tgtaaggtga tatttcatta tagttttgat ttgcatttcc
ctaatgatta 1080 gtgatgttaa gcatctcttc atgtgcctat tggccatttg
tatatcttct ttaaaaatat 1140 atatatactc attcctttgc ccatttttga
attatgttta ttttttgtta ttgagtttca 1200 atacttttct atataaccta
ggtattaatc ctttatcaga cttaagattt gcaaatattc 1260 tctttcattc
cacaggttgc taattctctc tgttggtaat atcttttgat gctgttgtgt 1320
ccagaattga ttcattcctg tgggttcttg gtctcactga cttcaagaat aaagctgcgg
1380 accctagtgg tgagtgttac acttcttata gatggtgttt ccggagtttg
ttccttcaga 1440 tgtgtccaga gtttcttcct tccaatgggt tcatggtctt
gctgacttca ggaatgaagc 1500 cgcagacctt cgcagtgagg tttacagctc
ttaaaggtgg cgtgtccaga gttgtttgtt 1560 ccccctggtg ggttcgtggt
cttgctgact tcaggaatga agccgcagac cctcgcagtg 1620 agtgttacag
ctcataaagg tagtgcggac acagagtgag ctgcagcaag atttactgtg 1680
aagagcaaaa gaacaaagct tccacagcat agaaggacac cccagcgggt tcctgctgct
1740 ggctcaggtg gccagttatt attcccttat ttgccctgcc cacatcctgc
tgattggtcc 1800 attttacaga gtactgattg gtccatttta cagagtgctg
attggtgcat ttacaatcct 1860 ttagctagac acagagtgct gattgctgca
ttcttacaga gtgctgattg gtgcatttac 1920 agtcctttag ctagatacag
aacgctgatt gctgcgtttt ttacagagtg ctgattggtg 1980 catttacaat
cctttagcta gacacagtgc tgattggtgg gtttttacag agtgctgatt 2040
ggtgcgtctt tacagagtgc tgattggtgc atttacaatc ctttagctag acacagagtg
2100 ctgattggtg cgtttataat cctctagcta gacagaaaag ttttccaagt
ccccacctga 2160 ccgagaagcc ccactggctt cacctctcac tgttatactt
tggacatttg tccccccaaa 2220 atctcatgtt gaaatgtaac ccctaatgtt
ggaactgagg ccagactgga tgtggctggg 2280 ccatgggga 2289 52 1184 DNA
Homo sapiens misc_feature sequence of STAR52 52 ctcttctttg
tttttttatt ttggggtgtg tgggtacgtg taagatgaga aatgtacaaa 60
cacaagtatt tcagaaactc caagtaatat tctgtctgtg agttcacggt aaataaataa
120 aaagggcaaa gtgacagaaa tacaggatta ttaaaagcaa aataatgttc
tttgaaatcc 180 cccccttggt gtatttttta tcttaggatg cagcactttc
agcatgccca agtattgaaa 240 gcagtgtttt tacgctacca cggtaatttt
atttagaaac cccatgttca cttttagttt 300 taaaatggtc tttatgacat
aaaattatca gcattcatat ttttgtgttt taatattcct 360 ttggctactt
attgaaacag taaacattac gaaaattagt aaacaaatct ttgatagttg 420
cttatttttg tttaattgaa tgtttatttt attaggtaaa tatacaatca aatttattta
480 aaaataatga ggaaaagaat acttttcttt cgctttgcga aagcaaagtg
atttttcatt 540 cttctccgtc cgattccttc tcttccagct gccacagccg
actgacaggc tcccggcggc 600 ctgaggagta gtatgcaaat tttggatgat
tgacacctac agtagaagcc aatcacgtca 660 aagtaggatg ctgattggtt
gacaacaata ggcgtaaacc ttgacgtttt aaaaacctga 720 cacccaatcc
aggcgattca tgcaaataaa ggaagggagt cacattacca ggggccagag 780
agacttgagt acgacctcac gtgttcagtg gtggatattg cacagacgtc tgcaaggtct
840 atataaacgc tacataatgt tcaactcaat tgcttgcctt ggcctttccc
aaacttgtca 900 ctggaatata aattatccct tttttaaaaa taaaaaaata
agaattatgt agtgcacata 960 tatgatggtt catgtagaaa tctaaatgga
cttccaacgc atggaatttt cctatttccc 1020 cctttcttta aattaatcct
cagtgaagga ggctgttttc ccctagattt caaaaggacg 1080 agatttacag
agcctttcct tggagaaacc cgctctaggc acagatggtc agtaaattta 1140
gcttcttcag cgaagttcca catggcaccg ccagatggca taag 1184 53 1431 DNA
Homo sapiens misc_feature sequence of STAR53 53 ccctgaggaa
gatgacgagt aactccgtaa gagaaccttc cactcatccc ccacatccct 60
gcagacgtgc tattctgtta tgatactggt atcccatctg tcacttgctc cccaaatcat
120 tcccttctta caattttcta ctgtacagca ttgaggctga acgatgagag
atttcccatg 180 ctctttctac tccctgccct gtatatatcc ggggatcctc
cctacccagg atgctgtggg 240 gtcccaaacc ccaagtaagc cctgatatgc
gggccacacc tttctctagc ctaggaattg 300 ataacccagg cgaggaagtc
actgtggcat gaacagatgg ttcacttcga ggaaccgtgg 360 aaggcgtgtg
caggtcctga gatagggcag aatcggagtg tgcagggtct gcaggtcagg 420
aggagttgag attgcgttgc cacgtggtgg gaactcactg ccacttattt ccttctctct
480 tcttgcctca gcctcaggga tacgacacat gcccatgatg agaagcagaa
cgtggtgacc 540 tttcacgaac atgggcatgg ctgcggaccc ctcgtcatca
ggtgcatagc aagtgaaagc 600 aagtgttcac aacagtgaaa agttgagcgt
catttttctt agtgtgccaa gagttcgatg 660 ttagcgttta cgttgtattt
tcttacactg tgtcattctg ttagatacta acattttcat 720 tgatgagcaa
gacatactta atgcatattt tggtttgtgt atccatgcac ctaccttaga 780
aaacaagtat tgtcggttac ctctgcatgg aacagcatta ccctcctctc tccccagatg
840 tgactactga gggcagttct gagtgtttaa tttcagattt tttcctctgc
atttacacac 900 acacgcacac aaaccacacc acacacacac acacacacac
acacacacac acacacacac 960 acacaccaag taccagtata agcatctgcc
atctgctttt cccattgcca tgcgtcctgg 1020 tcaagctccc ctcactctgt
ttcctggtca gcatgtactc ccctcatccg attcccctgt 1080 agcagtcact
gacagttaat aaacctttgc aaacgttccc cagttgtttg ctcgtgccat 1140
tattgtgcac acagctctgt gcacgtgtgt gcatatttct ttaggaaaga ttcttagaag
1200 tggaattgct gtgtcaaagg agtcatttat tcaacaaaac actaatgagt
gcgtcctcgt 1260 gctgagcgct gttctaggtg ctggagcgac gtcagggaac
aaggcagaca ggagttcctg 1320 acccccgttc tagaggagga tgtttccagt
tgttgggttt tgtttgtttg tttcttctag 1380 agatggtggt cttgctctgt
ccaggctaga gtgcagtggc atgatcatag c 1431 54 975 DNA Homo sapiens
misc_feature sequence of STAR54 54 ccataaaagt gtttctaaac tgcagaaaaa
tccccctaca gtcttacagt tcaagaattt 60 tcagcatgaa atgcctggta
gattacctga ctttttttgc caaaaataag gcacagcagc 120 tctctcctga
ctctgacttt ctatagtcct tactgaatta tagtccttac tgaattcatt 180
cttcagtgtt gcagtctgaa ggacacccac attttctctt tgtctttgtc aattctttgt
240 gttgtaaggg caggatgttt aaaagttgaa gtcattgact tgcaaaatga
gaaatttcag 300 agggcatttt gttctctaga ccatgtagct tagagcagtg
ttcacactga ggttgctgct 360 aatgtttctg cagttcttac caatagtatc
atttacccag caacaggata tgatagagga 420 cttcgaaaac cccagaaaat
gttttgccat atatccaaag ccctttggga aatggaaagg 480 aattgcgggc
tcccattttt atatatggat agatagagac caagaaagac caaggcaact 540
ccatgtgctt tacattaata aagtacaaaa tgttaacatg taggaagtct aggcgaagtt
600 tatgtgagaa ttctttacac taattttgca acattttaat gcaagtctga
aattatgtca 660 aaataagtaa aaatttttac aagttaagca gagaataaca
atgattagtc agagaaataa 720 gtagcaaaat cttcttctca gtattgactt
ggttgctttt caatctctga ggacacagca 780 gtcttcgctt ccaaatccac
aagtcacatc agtgaggaga ctcagctgag actttggcta 840 atgttggggg
gtccctcctg tgtctcccca ggcgcagtga gcctgcaggc cgacctcact 900
cgtggcacac aactaaatct ggggagaagc aacccgatgc cagcatgatg cagatatctc
960 agggtatgat cggcc 975 55 501 DNA Homo sapiens misc_feature
sequence of STAR55 55 cctgaactca tgatccgccc acctcagcct cctgaagtgc
tgggattaca ggtgtgagcc 60 accacaccca gccgcaacac actcttgagc
aaccaatgtg tcataaaaga aataaaatgg 120 aaatcagaaa gtatcttgag
acagacaaaa atggaaacac aacataccaa aatttatggg 180 acacagcaaa
agcagtttta ggagggaagt ttatagtgat gaatacctac ctcaaaatca 240
ttagcctgat tggatgacac tacagtgtat aaatgaattg aaaaccacat tgtgccccat
300 acatatatac aatttttatt tgttaattaa aaataaaata aaactttaaa
aaagaagaaa 360 gagctcaaat aaacaaccta actttatacc tcaaggaaat
agaagagcca gctaagccca 420 aagttgacag aaggaaaaaa atattggcag
aaagaaatga aacagagact agaaagacaa 480 ttgaagagat cagcaaaact a 501 56
741 DNA Homo sapiens misc_feature sequence of STAR56 56 acacaggaaa
agatcgcaat tgttcagcag agctttgaac cggggatgac ggtctccctc 60
gttgcccggc aacatggtgt agcagccagc cagttatttc tctggcgtaa gcaataccag
120 gaaggaagtc ttactgctgt cgccgccgga gaacaggttg ttcctgcctc
tgaacttgct 180 gccgccatga agcagattaa agaactccag cgcctgctcg
gcaagaaaac gatggaaaat 240 gaactcctca aagaagccgt tgaatatgga
cgggcaaaaa agtggatagc gcacgcgccc 300 ttattgcccg gggatgggga
gtaagcttag tcagccgttg tctccgggtg tcgcgtgcgc 360 agttgcacgt
cattctcaga cgaaccgatg actggatgga tggccgccgc agtcgtcaca 420
ctgatgatac ggatgtgctt ctccgtatac accatgttat cggagagctg ccaacgtatg
480 gttatcgtcg ggtatgggcg ctgcttcgca gacaggcaga acttgatggt
atgcctgcga 540 tcaatgccaa acgtgtttac cggatcatgc gccagaatgc
gctgttgctt gagcgaaaac 600 ctgctgtacc gccatcgaaa cgggcacata
caggcagagt ggccgtgaaa gaaagcaatc 660 agcgatggtg ctctgacggg
ttcgagttct gctgtgataa cggagagaga ctgcgtgtca 720 cgttcgcgct
ggactgctgt g 741 57 1365 DNA Homo sapiens misc_feature sequence of
STAR57 57 tccttctgta aataggcaaa atgtatttta gtttccacca cacatgttct
tttctgtagg 60 gcttgtatgt tggaaatttt atccaattat tcaattaaca
ctataccaac aatctgctaa 120 ttctggagat gtggcagtga ataaaaaagt
tatagtttct gattttgtgg agcttggact 180 ttaatgatgg acaaaacaac
acattcttaa atatatattt catcaaaatt atagtgggtg 240 aattatttat
atgtgcattt acatgtgtat gtatacataa atgggcggtt actggctgca 300
ctgagaatgt acacgtggcg cgaacgaggc tgggcggtca gagaaggcct cccaaggagg
360 tggctttgaa gctgagtggt gcttccacgt gaaaaggctg gaaagggcat
tccaagaaaa 420 ggctgaggcc agcgggaaag aggttccagt gcgctctggg
aacggaaagc gcacctgcct 480 gaaacgaaaa tgagtgtgct gaaataggac
gctagaaagg gaggcagagg ctggcaaaag 540 cgaccgagga ggagctcaaa
ggagcgagcg gggaaggccg ctgtggagcc tggaggaagc 600 acttcggaag
cgcttctgag cgggtaaggc cgctgggagc atgaactgct gagcaggtgt 660
gtccagaatt cgtgggttct tggtctcact gacttcaaga atgaagaggg accgcggacc
720 ctcgcggtga gtgttacagc tcttaaggtg gcgcgtctgg agtttgttcc
ttctgatgtt 780 cggatgtgtt cagagtttct tccttctggt gggttcgtgg
tctcgctggc tcaggagtga 840 agctgcagac cttcgcggtg agtgttacag
ctcataaaag cagggtggac tcaaagagtg 900 agcagcagca agatttattg
caaagaatga aagaacaaag cttccacact gtggaagggg 960 accccagcgg
gttgccactg ctggctccgc agcctgcttt tattctctta tctggcccca 1020
cccacatcct gctgattggt agagccgaat ggtctgtttt gacggcgctg attggtgcgt
1080 ttacaatccc tgcgctagat acaaaggttc tccacgtccc caccagatta
gctagataga 1140 gtctccacac aaaggttctc caaggcccca ccagagtagc
tagatacaga gtgttgattg 1200 gtgcattcac aaaccctgag ctagacacag
ggtgatgact ggtgtgttta caaaccttgc 1260 ggtagataca gagtatcaat
tggcgtattt acaatcactg agctaggcat aaaggttctc 1320 caggtcccca
ccagactcag gagcccagct ggcttcaccc agtgg 1365 58 1401 DNA Homo
sapiens misc_feature sequence of STAR58 58 aagtttacct tagccctaaa
ttatttcatt gtgattggca ttttaggaaa tatgtattaa 60 ggaatgtctc
ttaggagata aggataacat atgtctaaga aaattatatt gaaatattat 120
tacatgaact aaaatgttag aactgaaaaa aaattattgt aactccttcc agcgtaggca
180 ggagtatcta gataccaact ttaacaactc aactttaaca acttcgaacc
aaccagatgg 240 ctaggagatt cacctattta gcatgatatc ttttattgat
aaaaaaatat aaaacttcca 300 ttaaattttt aagctactac aatcctatta
aattttaact taccagtgtt ctcaatgcta 360 cataatttaa aatcattgaa
atcttctgat tttaactcct cagtcttgaa atctacttat 420 ttttagttac
atatatatcc aatctactgc cgctagtaga agaagcttgg aatttgagaa 480
aaaaatcaga cgttttgtat attctcatat tcactaattt attttttaaa tgagtttctg
540 caatgcatca agcagtggca aaacaggaga aaaattaaaa ttggttgaaa
agatatgtgt 600 gccaaacaat cccttgaaat ttgatgaagt gactaatcct
gagttattgt ttcaaatgtg 660 tacctgttta tacaagggta tcacctttga
aatctcaaca ttaaatgaaa ttttataagc 720 aatttgttgt aacatgatta
ttataaaatt ctgatataac attttttatt acctgtttag 780 agtttaaaga
gagaaaagga gttaagaata attacatttt cattagcatt gtccgggtgc 840
aaaaacttct aacactatct tcaaatcttt ttctccattg ccttctgaac atacccactt
900 gggtatctca ttagcactgc aaattcaaca ttttcgattg ctaatttttc
tccctaaata 960 tttatttgtt ttctcagctt tagccaatgt ttcactattg
accatttgct caagtatagt 1020 gacgcttcaa tgaccttcag agagctgttt
cagtccttcc tggactactt gcatgcttcc 1080 aacaaaatga agcactcttg
atgtcagtca ctcaaataaa tggaaatggg cccatttact 1140 aggaatgtta
acagaataaa aagatagacg tgacaccagt tgcttcagtc catctccatt 1200
tacttgctta aggcctggcc atatttctca cagttgatat ggcgcagggc acatgtttaa
1260 atggctgttc ttgtaggatg gtttgactgt tggattcctc atcttccctc
tccttaggaa 1320 ggaaggttac agtagtactg ttggctcctg gaatatagat
tcataaagaa ctaatggagt 1380 atcatctccc actgctcttg t 1401 59 866 DNA
Homo sapiens misc_feature sequence of STAR59 59 gagatcacgc
cactgcactc cagcctgggg gacagagcaa gactccatct cagaaacaaa 60
caaacacaca aagccagtca aggtgtttaa ttcgacggtg tcaggctcag gtctcttgac
120 aggatacatc cagcacccgg gggaaacgtc gatgggtggg gtggaatcta
ttttgtggcc 180 tcaagggagg gtttgagagg tagtcccgca agcggtgatg
gcctaaggaa gcccctccgc 240 ccaagaagcg atattcattt ctagcctgta
gccacccaag agggagaatc gggctcgcca 300 cagaccccac aacccccaac
ccaccccacc cccacccctc ccacctcgtg aaatgggctc 360 tcgctccgtc
aggctctagt cacaccgtgt ggttttggaa cctccagcgt gtgtgcgtgg 420
gttgcgtggt ggggtggggc cggctgtgga cagaggaggg gataaagcgg cggtgtcccg
480 cgggtgcccg ggacgtgggg cgtggggcgt gggtggggtg gccagagcct
tgggaactcg 540 tcgcctgtcg ggacgtctcc cctcctggtc ccctctctga
cctacgctcc acatcttcgc 600 cgttcagtgg ggaccttgtg ggtggaagtc
accatccctt tggactttag ccgacgaagg 660 ccgggctccc aagagtctcc
ccggaggcgg ggccttgggc aggctcacaa ggatgctgac 720 ggtgacggtt
ggtgacggtg atgtacttcg gaggcctcgg gccaatgcag aggtatccat 780
ttgacctcgg tgggacaggt cagctttgcg gagtcccgtg cgtccttcca gagactcatc
840 cagcgctagc aagcatggtc ccgagg 866 60 2067 DNA Homo sapiens
misc_feature sequence of STAR60 60 agcagtgcag aactggggaa gaagaagagt
ccctacacca cttaatactc aaaagtactc 60 gcaaaaaata acacccctca
ccaggtggca tnattactct ccttcattga gaaaattagg 120 aaactggact
tcgtagaagc taattgcttt atccagagcc acctgcatac aaacctgcag 180
cgccacctgc atacaaacct gtcagccgac cccaaagccc tcagtcgcac caagcctctg
240 ctgcacaccc tcgtgccttc acactggccg ttccccaagc ctggggcata
ctncccagct 300 ctgagaaatg tattcatcct tcaaagccct gctcatgtgt
cctnntcaac aggaaaatct 360 cccatgagat gctctgctat ccccatctct
cctgccccat agcttaggca nacttctgtg 420 gtggtgagtc ctgggctgtg
ctgtgatgtg ttcgcctgcn atgtntgttc ttccccacaa 480 tgatgggccc
ctgaattctc tatctctagc acctgtgctc agtaaaggct tgggaaacca 540
ggctcaaagc ctggcccaga tgccaccttt tccagggtgc ttccgggggc caccaaccag
600 agtgcagcct tctcctccac caggaactct tgcagcccca cccctgagca
cctgcacccc 660 attacccatc tttgtttctc cgtgtgatcg tattattaca
gaattatata ctgtattctt 720 aatacagtat ataattgtat aattattctt
aatacagtat ataattatac aaatacaaaa 780 tatgtgttaa tggaccgttt
atgttactgg taaagcttta agtcaacagt gggacattag 840 ttaggttttt
ggcgaagtca aaagttatat gtgcattttc aacttcttga ggggtcggta 900
cntctnaccc ccatgttgtt caanggtcaa ctgtctacac atatcatagc taattcacta
960 cagaaatgtt agcttgtgtc actagtatct ccccttctca taagcttaat
acacatacct 1020 tgagagagct cttggccatc tctactaatg actgaagttt
ttatttatta tagatgtcat 1080 aataggcata aaactacatt acatcattcg
agtgccaatt ttgccacctt gaccctcttt 1140 tgcaaaacac caacgtcagt
acacatatga agaggaaact gcccgagaac tgaagttcct 1200 gagaccagga
gctgcaggcg ttagatagaa tatggtgacg agagttacga ggatgacgag 1260
agtaaatact tcatactcag tacgtgccaa gcactgctat aagcgctctg tatgtgtgaa
1320 gtcatttaat cctcacagca tcccacggtg taattatttt cattatcccc
atgagggaac 1380 agaaactcag aacggttcaa cacatatgcg agaagtcgca
gccggtcagt gagagagcag 1440 gttcccgtcc aagcagtcag accccgagtg
cacactctcg acccctgtcc agcagactca 1500 ctcgtcataa ggcggggagt
gntctgtttc agccagatgc tttatgcatc tcagagtacc 1560 caaaccatga
aagaatgagg cagtattcan gagcagatgg ngctgggcag taaggctggg 1620
cttcagaata gctggaaagc tcaagtnatg ggacctgcaa gaaaaatcca ttgtttngat
1680 aaatagccaa agtccctagg ctgtaagggg aaggtgtgcc aggtgcaagt
ggagctctaa 1740 tgtaaaatcg cacctgagtc tcctggtctt atgagtnctg
ggtgtacccc agtgaaaggt 1800 cctgctgcca ccaagtgggc catggttcag
ctgtgtaagt gctgagcggc agccggaccg 1860 cttcctctaa cttcacctcc
aaaggcacag tgcacctggt tcctccagca ctcagctgcg 1920 aggcccctag
ccagggtccc ggcccccggc ccccggcagc tgctccagct tccttcccca 1980
cagcattcag gatggtctgc gttcatgtag acctttgttt tcagtctgtg ctccgaggtc
2040 actggcagca ctagccccgg ctcctgt 2067 61 1470 DNA Homo sapiens
misc_feature sequence of STAR61 61 cagcccccac atgcccagcc ctgtgctcag
ctctgcagcg gggcatggtg ggcagagaca 60 cagaggccaa ggccctgctt
cggggacggt gggcctggga tgagcatggc cttggccttc 120 gccgagagtn
ctcttgtgaa ggaggggtca ggaggggctg ctgcagctgg ggaggagggc 180
gatggcactg tggcangaag tgaantagtg tgggtgcctn gcaccccagg cacggccagc
240 ctggggtatg gacccggggc cntctgttct agagcaggaa ggtatggtga
ggacctcaaa 300 aggacagcca ctggagagct ccaggcagag gnacttgaga
ggccctgggg ccatcctgtc 360 tcttttctgg gtctgtgtgc tctgggcctg
ggcccttcct ctgctccccc gggcttggag 420 agggctggcc ttgcctcgtg
caaaggacca ctctagactg gtaccaagtc tggcccatgg 480 cctcctgtgg
gtgcaggcct gtgcgggtga cctgagagcc agggctggca ggtcagagtc 540
aggagaggga tggcagtgga tgccctgtgc aggatctgcc taatcatggt gaggctggag
600 gaatccaaag tgggcatgca ctctgcactc atttctttat tcatgtgtgc
ccatcccaac 660 aagcagggag cctggccagg agggcccctg ggagaaggca
ctgatgggct gtgttccatt 720 taggaaggat ggacggttgt gagacgggta
agtcagaacg ggctgcccac ctcggccgag 780 agggccccgt ggtgggttgg
caccatctgg gcctggagag ctgctcagga ggctctctag 840 ggctgggtga
ccaggnctgg ggtacagtag ccatgggagc aggtgcttac ctggggctgt 900
ccctgagcag gggctgcatt gggtgctctg tgagcacaca cttctctatt cacctgagtc
960 ccnctgagtg atgagnacac ccttgttttg cagatgaatc tgagcatgga
gatgttaagt 1020 ggcttgcctg agccacacag cagatggatg gtgtagctgg
gacctgaggg caggcagtcc 1080 cagcccgagg acttcccaag gttgtggcaa
actctgacag catgacccca gggaacaccc 1140 atctcagctc tggtcagaca
ctgcggagtt gtgttgtaac ccacacagct ggagacagcc 1200 accctagccc
cacccttatc ctctcccaaa ggaacctgcc ctttcccttc attttcctct 1260
tactgcattg agggaccaca cagtgtggca gaaggaacat gggttcagga cccagatgga
1320 cttgcttcac agtgcagccc tcctgtcctc ttgcagagtg cgtcttccac
tgtgaagttg 1380 ggacagtcac accaactcaa tactgctggg cccgtcacac
ggtgggcagg caacggatgg 1440 cagtcactgg ctgtgggtct gcagaggtgg 1470 62
1011 DNA Homo sapiens misc_feature sequence of STAR62 62 agtgtcaaat
agatctacac aaaacaagat aatgtctgcc catttttcca aagataatgt 60
ggtgaagtgg gtagagagaa atgcatccat tctccccacc caacctctgc taaattgtcc
120 atgtcacagt actgagacca gggggcttat tcccagcggg cagaatgtgc
accaagcacc 180 tcttgtctca atttgcagtc taggccctgc tatttgatgg
tgtgaaggct tgcacctggc 240 atggaaggtc cgttttgtac ttcttgcttt
agcagttcaa agagcaggga gagctgcgag 300 ggcctctgca gcttcagatg
gatgtggtca gcttgttgga ggcgccttct gtggtccatt 360 atctccagcc
cccctgcggt gttgctgttt gcttggcttg tctggctctc catgccttgt 420
tggctccaaa atgtcatcat gctgcacccc aggaagaatg tgcaggccca tctcttttat
480 gtgctttggg ctattttgat tccccgttgg gtatattccc taggtaagac
ccagaagaca 540 caggaggtag ttgctttggg agagtttgga cctatgggta
tgaggtaata gacacagtat 600 cttctctttc atttggtgag actgttagct
ctggccgcgg actgaattcc acacagctca 660 cttgggaaaa ctttattcca
aaacatagtc acattgaaca ttgtggagaa tgagggacag 720 agaagaggcc
ctagatttgt acatctgggt gttatgtcta taaatagaat gctttggtgg 780
tcaactagac ttgttcatgt tgacatttag tcttgccttt tcggtggtga tttaaaaatt
840 atgtatatct tgtttggaat atagtggagc tatggtgtgg cattttcatc
tggctttttg 900 tttagctcag cccgtcctgt tatgggcagc cttgaagctc
agtagctaat gaagaggtat 960 cctcactccc tccagagagc ggtcccctca
cggctcattg agagtttgtc a 1011 63 1410 DNA Homo sapiens misc_feature
sequence of STAR63 63 ccacagcctg atcgtgctgt cgatgagagg aatctgctct
aagggtctga gcggagggag 60 atgccgaagc tttgagcttt ttgtttctgg
cttaaccttg gtggattttc accctctggg 120 cattacctct tgtccagggg
aggggctggg ggagtgcctg gagctgtagg gacagagggc 180 tgagtggggg
ggactgcttg ggctgaccac ataatattct gctgcgtatt aatttttttt 240
tgagacagtc tttctctgtt gcccaggctg gagtgtaatg gcttgatagc tcactgccac
300 ctccgcctcc tgggttcaag tgattctcct gcttcagctt ccggagtagc
tgggactgca 360 ggtgcccgcc accatggctg gctaattttt gtatttttat
tagcaatggg gttttgctat 420 gttgcccagg ccggtcccga actcctgccc
tcaagtgata cacctgcctc ggcctcccaa 480 agtgctggga ttagaggctt
gagccactgc gcctggccag ctgcatattg ttaattagac 540 ataaaatgca
aaataagatg atataaacac aaaggtgtga aataagatgg acacctgctg 600
agcgcgcctg tcctgaagca tcgcccctct gcaaaagcag gggtcagcat gtgttctccg
660 gtccttgctc ttacagagga gtgagctgcc tatgcgtctt ccagccactt
cctgggctgc 720 tcagaggcct ctcacgggtg ttctgggttg ctgccacttg
caggggtgct gaggcggggc 780 tcctcccgtg cggggcatgt ccaggccgcc
ctctctgaag gcttggcagg tacaggtggg 840 agtgggggtc tctgggctgc
tgtggggact gggcaggctc ctggaagacc tccctgtgtt 900 tgggctgaaa
gcgcagcccg aggggaggtc cccagggagg ccgctgtcgg gggtgggggc 960
ttggaggagg gaggggccga ggagccggcg acactccgtg acggcccagg aacgtcccta
1020 aacaaggcgc cgcgttctcg atggggtggg gtccgctttc ttttctcaaa
agctgcagtt 1080 actccatgct cggaggactg gcgtccgcgc cctgttccaa
tgctgccccg gggccctggc 1140 cttggggaat cggggccttg gactggaccc
tgggggcttc gcggagccgg gcctggcggg 1200 gcgagcggag cagaggctgg
gcagccccgg ggaagcgctc gccaaagccg ggcgctgctc 1260 ccagagcgcg
aggtgcagaa ccagaggctg gtcccgcggc gctaacgaga gaagaggaag 1320
cgcgctgtgt agagggcgcc caccccgtgg ggcgaacccc cttcctcaac tccatggacg
1380 gggctcatgg gttcccagcg gctcagacgc 1410 64 1414 DNA Homo sapiens
misc_feature sequence of STAR64 64 tggatcagat ttgttttata ccctcccttc
tactgctctg agagttgtac atcacagtct 60 actgtatctg tttcccatta
ttataatttt tttgcactgt gcttgcctga agggagcctc 120 aagttcatga
gtctccctac cctcctccca aatgagacat ggacctttga atgctttcct 180
gggaccacca ccccaccttt catgctgctg ttatccagga ttttagttca acagtgtttt
240 aaccccccaa atgagtcatt tttattgttt cgtatagtga atgtgtattt
gggtttgctt 300 atatggtgac ctgtttattt gctcctcatt gtacctcatg
ctctgctctt tccttctaga 360 ttcagtctct ttcctaatga ggtgtctcgc
agcaattctt tacaagacag ccaagatagg 420 ccagctctca gagcacttgt
tgtctgaaaa agtcttgtct tatttaattt ctttttctta 480 gagatggggt
ctcattatgt tacccacact ggtctcaaac ttctggctta aagcggtcct 540
cccaccttgg cctcccaaag tgctaggatt acaggcgtga gcgacctcgt ccagcctgtc
600 tgagaaagcg tttgttttgc ccttgctctc agatgacagt ttggggatag
aattctaggt 660 ggacggtttt tttccttcag ccctttgaag agtctgtatt
ttcattatct ccctgcatta 720 gatgttcttt tgcaagtaac gtgtcttttc
tctctgggta ttcttaaggt tttctctttg 780 cctttggtga gctgcagtgg
atttgctttt ttcaagaggt caagagaaag gaaagtgtga 840 ggtttctgtt
ttttactgac aatttgtttg ttgatttgtt ttcccaccca gaggttcctt 900
gccactttgc caggctggaa ggcagacttc ttctggtgtc ctgttcacag acggggcagc
960 ctgcggaagg ccctgccaca tgcagggcct cggtcctcat tcccttgcat
gtggacccgg 1020 gcgtgactcc tgttcaggct ggcacttccc agagctgagc
cccagcctga ccttcctccc 1080 atactgtctt cacaccccct cctttcttct
gatacctgga ggttttcctt tctttcctgt 1140 cacctccact tggattttaa
atcctctgtc tgtggaattg tattcggcac aggaagatgc 1200 ttgcaagggc
caggctcatc agccctgtcc ctgctgctgg aagcagcaca gcagagcctc 1260
atgctcaggc tgagatggag cagaggcctg cagacgagca cccagctcag ctggggttgg
1320 cgccgatggt ggagggtcct cgaaagctct ggggacgatg gcagagctat
tggcagggga 1380 gccgcagggt cttttgagcc cttaaaagat ctct 1414 65 1310
DNA Homo sapiens misc_feature sequence of STAR65 65 gtgaatgttg
atggatcaaa tatctttctg tgttgtttat caaagttaaa ataaatgtgg 60
tcatttaaag gacaaaagat gaggggttgg agtctgttca agcaaagggt atattaggag
120 aaaagcagaa ttctctccct gtgaagggac agtgactcct attttccacc
tcatttttac 180 taactctcct aactatctgc ttaggtagag atatatccat
gtacatttat aaaccacagt 240 gaatcatttg attttggaat aaagatagta
taaaatgtgt cccagtgttg atatacatca 300 tacattaaat atgtctggca
gtgttctaat tttacagttg tccaaagata atgttagggc 360 atactggcta
tggatgaagc tccaatgttc agattgcaaa gaaacttaga attttactaa 420
tgaaaccaaa tacatcccaa gaaatttttc agaagaaaaa aagagaaact agtagcaaag
480 taaagaatca ccacaatatc atcagatttt ttttatatgt agaatattta
ttcagttctt 540 ttttcaagta caccttgtct tcattcattg tactttattt
tttgtgaagg tttaaattta 600 tttcttctat gtgtttagtg atatttaaaa
tttttattta atcaagttta tcagaaagtt 660 ctgttagaaa atatgacgag
gctttaattc cgccatctat attttccgct attatataaa 720 gataattgtt
ttctcttttt aaaacaactt gaattgggat tttatatcat aattttttaa 780
tgtctttttt tattatactt taagttctgg gatacatgtg cagaacgtgc aggtgtgtta
840 catagatata cacgtgccat ggtggtttgc tgcacccact aacctgttat
cgacattagg 900 tatttctcct aatgctatca ccccctattt ccccaccccc
cgagaggccc cagtgtgtga 960 tgttctcctc cctgtgtcca tgtgttctca
ttgttcatct cccacttatg gtatctacca 1020 taaccttgaa attgtcttat
gcattcactt gtttggttgt tatatagcct ccatcaggac 1080 agggatattt
gctgctgctt cttttttttt tctttttgag acagtcttgc tccgtcatcc 1140
aggctggagt gcttctcggc tcaatgcaac ctccacctcc caggtttaag cgattctcca
1200 acttcagcct cccaaatggc tgggactgca ggcatgcacc actacacctg
gctaattttt 1260 gtatttgtaa tagagacaat gtttcaccat gttggccagg
ctggtctcga 1310 66 1917 DNA Homo sapiens misc_feature sequence of
STAR67 66 aggatcctaa aattttgtga ccctagagca agtactaact atgaaagtga
aatagagaat 60 gaaggaatta tttaattaag tccagcaaaa cccaaccaaa
tcatctgtaa aatatatttg 120 ttttcaacat ccaggtattt tctgtgtaaa
aggttgagtt gtatgctgac ttattgggaa 180 aaataattga gttttcccct
tcactttgcc agtgagagga aatcagtact gtaattgtta 240 aaggttaccc
atacctacct ctactaccgt ctagcatagg taaagtaatg tacactgtga 300
agtttcctgc ttgactgtaa tgttttcagt ttcatcccat tgattcaaca gctatttatt
360 cagcacttac tacaaccatg ctggaaaccc aagagtaaat aggctgtgtt
actcaacagg 420 actgaggtac agccgaactg tcaggcaagg ttgctgtcct
ttggacttgc ctgctttctc 480 tctatgtagg aagaagaaat ggacataccg
tccaggaaat agatatatgt tacatttcct 540 tattccataa ttaatattaa
taaccctgga cagaaactac caagtttcta gacccttata 600 gtaccacctt
accctttctg gatgaatcct tcacatgttg atacatttta tccaaatgaa 660
aattttggta ctgtaggtat aacagacaaa gagagaacag aaaactagag atgaagtttg
720 ggaaaaggtc aagaaagtaa ataatgcttc tagaagacac aaaaagaaaa
atgaaatggt 780 aatgttggga aagttttaat acattttgcc ctaaggaaaa
aaactacttg ttgaaattct 840 acttaagact ggaccttttc tctaaaaatt
gtgcttgatg tgaattaaag caacacaggg 900 aaatttatgg gctccttcta
agttctaccc aactcaccgc aaaactgttc ctagtaggtg 960 tggtatactc
tttcagattc tttgtgtgta tgtatatgtg tgtgtgtgtg tgtgtttgta 1020
tgtgtacagt ctatatacat atgtgtacct acatgtgtgt atatataaat atatatttac
1080 ctggatgaaa tagcatatta tagaatattc ttttttcttt aaatatatat
gtgcatacat 1140 atgtatatgc acatatatac ataaatgtag atatagctag
gtaggcattc atgtgaaaca 1200 aagaagccta ttacttttta atggttgcat
gatattccat cataggagta tagtacaact 1260 tatgtaacac acatttggct
tgttgtaaaa ttttggtatt aataaaatag cacatatcat 1320 gcaaagacac
ccttgcatag gtctattcat tctttgattt ttaccttagg acaaaattta 1380
aaagtagaat ttctgggtca agcagtatgc tcatttaaaa tgtcattgca tatttccaaa
1440 ttgtcctcca gaaaagtagt aacagtaaca attgatggac tgcgtgtttt
ctaaaacttg 1500 catttttttc cttattggtg aggtttggca ttttccatat
gtttattggc attttaattt 1560 tttttggttc atgtctttta ttcccttcct
gcaaatttgt ggtgtgtctc aactttattt 1620 atactctcat tttcataatt
ttctaaagga atttgacttt aaaaaaataa gacagccaat 1680 gctttggttt
aatttcattg ctgctttttg aagtgactgc tgtgttttta tatactttta 1740
tattttgttg ttttagcaaa ttcttctata ttataattgt gtatgctgga acaaaaagtt
1800 atatttctta atctagataa aatatttcaa gatgttgtaa ttacagtccc
ctctaaaatc 1860 atataaatag acgcatagct gtgtgatttg taattagtta
tgtccattga tagatcc 1917 67 26 DNA Artificial oligo for making
linker containing MCSII of pd2EGFP-link 67 gtacggatat cagatcttta
attaag 26 68 24 DNA Artificial oligo for making linker containing
MCSII of pd2EGFP-link 68 gtaccttaat taaagatctg atat 24 69 52 DNA
Artificial primer for amplification of 0.37 kb from pd2EGFP 69
gatcagatct ggcgcgccat ttaaatcgtc tcgcgcgttt cggtgatgac gg 52 70 41
DNA Artificial primer for amplification of 0.37 kb from pd2EGFP 70
aggcggatcc gaatgtattt agaaaaataa acaaataggg g 41 71 36 DNA
Artificial primer for amplifying zeocin resistance gene ORF 71
gatcggatcc ttcgaaatgg ccaagttgac cagtgc 36 72 32 DNA Artificial
primer for amplifying zeocin resistance gene ORF 72 aggcgcggcc
gcaattctca gtcctgctcc tc 32 73 40 DNA Artificial primer for
amplifying d2EGFP ORF 73 gatcgaattc tcgcgaatgg tgagcaagca
gatcctgaag 40 74 52 DNA Artificial primer for amplifying d2EGFP ORF
74 aggcgaattc accggtgttt aaacttacac ccactcgtgc aggctgccca gg 52 75
41 DNA Artificial primer for amplifying d2EGFP gene 75 ttggttggtc
atgaatggtg agcaagggcg aggagctgtt c 41 76 36 DNA Artificial primer
for amplifying d2EGFP gene 76 attctctaga ctacacattg atcctagcag
aagcac 36 77 42 DNA Artificial oligo for preparing linker for
creating MCS in pGL3-promoter-GFP 77 cgatatcttg gagatctact
agtggcgcgc cttgggctag ct 42 78 50 DNA Artificial oligo for
preparing linker for creating MCS in pGL3-promoter-GFP 78
gatcagctag cccaaggcgc gccactagta gatctccaag atatcgagct 50 79 40 DNA
Artificial primer for amplification of EF-1alfa promoter 79
gatcggcgcg ccatttaaat ccgaaaagtg ccacctgacg 40 80 34 DNA Artificial
primer for amplification of EF-1alfa promoter 80 aggcgggacc
ccctcacgac acctgaaatg gaag 34 81 51 DNA Artificial primer for
amplification of SV40 promoter 81 ttggttgggg cgcgccgcag caccatggcc
tgaaataacc tctgaaagag g 51 82 55 DNA Artificial primer for
amplification of SV40 promoter 82 ttggttggga gctcaagctt tttgcaaaag
cctaggcctc caaaaaagcc tcctc 55 83 11 DNA Artificial sequence around
startcodon of wild-type zeocin resistance gene 83 aaaccatggc c 11
84 50 DNA Artificial primer ZEOforwardMUT 84 gatctcgcga tacaggattt
atgttggcca agttgaccag tgccgttccg 50 85 26 DNA Artificial primer
ZEO-WTreverse 85 aggcgaattc agtcctgctc ctcggc 26 86 45 DNA
Artificial primer ZEO-LEUreverse 86 aggccccgcc cccacggctg
ctcgccgatc tcggtcaagg ccggc 45 87 45 DNA Artificial primer
ZEO-THRreverse 87 aggccccgcc cccacggctg ctcgccgatc tcggtggtgg ccggc
45 88 44 DNA Artificial primer ZEO-VALreverse 88 aggccccgcc
cccacggctg ctcgccgatc tcggtccacg ccgg 44 89 11 DNA Artificial
sequence around startcodon of wt d2EGFP 89 gaattcatgg g 11 90 49
DNA Artificial primer d2EGFPforwardBamHI 90 gatcggatcc tatgaggaat
tcgccaccat ggtgagcaag ggcgaggag 49 91 41 DNA Artificial primer
d2EGFPreverseNotI 91 aaggaaaaaa gcggccgcct acacattgat cctagcagaa g
41 92 57 DNA Artificial spacer sequence 92 tcgatccaaa gactgccaaa
tctagatccg agattttcag gagctaagga agctaaa 57 93 99 DNA Artificial
primer ZEOforwardBamHI-ATGmut/space 93 gatcggatcc ttggtttatg
tcgatccaaa gactgccaaa tctagatccg agattttcag 60 gagctaagga
agctaaagcc aagttgacca gtgaagttc 99 94 38 DNA Artificial primer
ZEOforwardBamHI-GTG 94 gatcggatcc accgtggcca agttgaccag tgccgttc 38
95 38 DNA Artificial primer ZEOforwardBamHI-TTG 95 gatcggatcc
accttggcca agttgaccag tgccgttc 38 96 35 DNA Artificial primer
BSDBamHIforward 96 gatcggatcc accatggcca agcctttgtc tcaag 35 97 25
DNA Artificial primer BSD150reverse 97 gtaaaatgat atacgttgac accag
25 98 25 DNA Artificial primer BSD150forward 98 ctggtgtcaa
cgtatatcat tttac 25 99 24 DNA Artificial primer BSD250reverse 99
gccctgttct cgtttccgat cgcg 24 100 24 DNA Artificial primer
BSD250forward 100 cgcgatcgga aacgagaaca gggc 24 101 24 DNA
Artificial primer BSD350reverse 101 gccgtcggct gtccgtcact gtcc 24
102 24 DNA Artificial primer BSD350forward 102 ggacagtgac
ggacagccga cggc 24 103 38 DNA Artificial primer BSD399reverse 103
gatcgaattc ttagccctcc cacacgtaac cagagggc 38 104 103 DNA Artificial
primer BSDforwardBamHIAvrII-ATGmut/space 104 gatcggatcc taggttggtt
tatgtcgatc caaagactgc caaatctaga tccgagattt 60 tcaggagcta
aggaagctaa agccaagcct ttgtctcaag aag 103 105 44 DNA Artificial
primer BSD399reverseEcoRIAvrII 105 gatcgaattc cctaggttag ccctcccaca
cgtaaccaga gggc 44 106 42 DNA Artificial primer
BSDforwardBamHIAvrII-GTG 106 gatcggatcc taggaccgtg gccaagcctt
tgtctcaaga ag 42 107 42 DNA Artificial primer
BSDforwardBamHIAvrII-TTG 107 gatcggatcc taggaccttg gccaagcctt
tgtctcaaga ag 42 108 375 DNA Artificial wt zeocin resistance gene
108 atg gcc aag ttg acc agt gcc gtt ccg gtg ctc acc gcg cgc gac gtc
48 Met Ala Lys Leu Thr Ser Ala Val Pro Val Leu Thr Ala Arg Asp Val
1 5 10 15 gcc gga gcg gtc gag ttc tgg acc gac cgg ctc ggg ttc tcc
cgg gac 96 Ala Gly Ala Val Glu Phe Trp Thr Asp Arg Leu Gly Phe Ser
Arg Asp 20 25 30 ttc gtg gag gac gac ttc gcc ggt gtg gtc cgg gac
gac gtg acc ctg 144 Phe Val Glu Asp Asp Phe Ala Gly Val Val Arg Asp
Asp Val Thr Leu 35 40 45 ttc atc agc gcg gtc cag gac cag gtg gtg
ccg gac aac acc ctg gcc 192 Phe Ile Ser Ala Val Gln Asp Gln Val Val
Pro Asp Asn Thr Leu Ala 50 55 60 tgg gtg tgg gtg cgc ggc ctg gac
gag ctg tac gcc gag tgg tcg gag 240 Trp Val Trp Val Arg Gly Leu Asp
Glu Leu Tyr Ala Glu Trp Ser Glu 65 70 75 80 gtc gtg tcc acg aac ttc
cgg gac gcc tcc ggg ccg gcc atg acc gag 288 Val Val Ser Thr Asn Phe
Arg Asp Ala Ser Gly Pro Ala Met Thr Glu 85 90 95 atc ggc gag cag
ccg tgg ggg cgg gag ttc gcc ctg cgc gac ccg gcc 336 Ile Gly Glu Gln
Pro Trp Gly Arg Glu Phe Ala Leu Arg Asp Pro Ala 100 105 110 ggc aac
tgc gtg cac ttc gtg gcc gag gag cag gac tga 375 Gly Asn Cys Val His
Phe Val Ala Glu Glu Gln Asp 115 120 109 124 PRT Artificial wt
zeocin resistance gene 109 Met Ala Lys Leu Thr Ser Ala Val Pro Val
Leu Thr Ala Arg Asp Val 1 5 10 15 Ala Gly Ala Val Glu Phe Trp Thr
Asp Arg Leu Gly Phe Ser Arg Asp 20 25 30 Phe Val Glu Asp Asp Phe
Ala Gly Val Val Arg Asp Asp Val Thr Leu 35 40 45 Phe Ile Ser Ala
Val Gln Asp Gln Val Val Pro Asp Asn Thr Leu Ala 50 55 60 Trp Val
Trp Val Arg Gly Leu Asp Glu Leu Tyr Ala Glu Trp Ser Glu 65 70 75 80
Val Val Ser Thr Asn Phe Arg Asp Ala Ser Gly Pro Ala Met Thr Glu 85
90 95 Ile Gly Glu Gln Pro Trp Gly Arg Glu Phe Ala Leu Arg Asp Pro
Ala 100 105 110 Gly Asn Cys Val His Phe Val Ala Glu Glu Gln Asp 115
120 110 399 DNA Artificial wt blasticidin resistance gene 110 atg
gcc aag cct ttg tct caa gaa gaa tcc acc ctc att gaa aga gca 48 Met
Ala Lys Pro Leu Ser Gln Glu Glu Ser Thr Leu Ile Glu Arg Ala 1 5 10
15 acg gct aca atc aac agc atc ccc atc tct gaa gac tac agc gtc gcc
96 Thr Ala Thr Ile Asn Ser Ile Pro Ile Ser Glu Asp Tyr Ser Val Ala
20 25 30 agc gca gct ctc tct agc gac ggc cgc atc ttc act ggt gtc
aat gta 144 Ser Ala Ala Leu Ser Ser Asp Gly Arg Ile Phe Thr Gly Val
Asn Val 35 40 45 tat cat ttt act ggg gga cct tgt gca gaa ctc gtg
gtg ctg ggc act 192 Tyr His Phe Thr Gly Gly Pro Cys Ala Glu Leu Val
Val Leu Gly Thr 50 55 60 gct gct gct gcg gca gct ggc aac ctg act
tgt atc gtc gcg atc gga 240 Ala Ala Ala Ala Ala Ala Gly Asn Leu Thr
Cys Ile Val Ala Ile Gly 65 70 75 80 aat gag aac agg ggc atc ttg agc
ccc tgc gga cgg tgc cga cag gtg 288 Asn Glu Asn Arg Gly Ile Leu Ser
Pro Cys Gly Arg Cys Arg Gln Val 85 90 95 ctt ctc gat ctg cat cct
ggg atc aaa gcc ata gtg aag gac agt gat 336 Leu Leu Asp Leu His Pro
Gly Ile Lys Ala Ile Val Lys Asp Ser Asp 100 105 110 gga cag ccg acg
gca gtt ggg att cgt gaa ttg ctg ccc tct ggt tat 384 Gly Gln Pro Thr
Ala Val Gly Ile Arg Glu Leu Leu Pro Ser Gly Tyr 115 120 125 gtg tgg
gag ggc taa 399 Val Trp Glu Gly 130 111 132 PRT Artificial wt
blasticidin resistance gene 111 Met Ala Lys Pro Leu Ser Gln Glu Glu
Ser Thr Leu Ile Glu Arg Ala 1 5 10 15 Thr Ala Thr Ile Asn Ser Ile
Pro Ile Ser Glu Asp Tyr Ser Val Ala 20 25 30 Ser Ala Ala Leu Ser
Ser Asp Gly Arg Ile Phe Thr Gly Val Asn Val 35 40 45 Tyr His Phe
Thr Gly Gly Pro Cys Ala Glu Leu Val Val Leu Gly Thr 50 55 60 Ala
Ala Ala Ala Ala Ala Gly Asn Leu Thr Cys Ile Val Ala Ile Gly 65 70
75 80 Asn Glu Asn Arg Gly Ile Leu Ser Pro Cys Gly Arg Cys Arg Gln
Val 85 90 95 Leu Leu Asp Leu His Pro Gly Ile Lys Ala Ile Val Lys
Asp Ser Asp 100 105 110 Gly Gln Pro Thr Ala Val Gly Ile Arg Glu Leu
Leu Pro Ser Gly Tyr 115 120 125 Val Trp Glu Gly 130 112 600 DNA
Artificial wt puromycin resistance gene 112 atg acc gag tac aag ccc
acg gtg cgc ctc gcc acc cgc gac gac gtc 48 Met Thr Glu Tyr Lys Pro
Thr Val Arg Leu Ala Thr Arg Asp Asp Val 1 5 10 15 ccc agg gcc gta
cgc acc ctc gcc gcc gcg ttc gcc gac tac ccc gcc 96 Pro Arg Ala Val
Arg Thr Leu Ala Ala Ala Phe Ala Asp Tyr Pro Ala 20 25 30 acg cgc
cac acc gtc gat ccg gac cgc cac atc gag cgg gtc acc gag 144 Thr Arg
His Thr Val Asp Pro Asp Arg His Ile Glu Arg Val Thr Glu 35 40 45
ctg caa gaa ctc ttc ctc acg cgc gtc ggg ctc gac atc ggc aag gtg 192
Leu Gln Glu Leu Phe Leu Thr Arg Val Gly Leu Asp Ile Gly Lys Val 50
55 60 tgg gtc gcg gac gac ggc gcc gcg gtg gcg gtc tgg acc acg ccg
gag 240 Trp Val Ala Asp Asp Gly Ala Ala Val Ala Val Trp Thr Thr Pro
Glu 65 70 75 80 agc gtc gaa gcg ggg gcg gtg ttc gcc gag atc ggc ccg
cgc atg gcc 288 Ser Val Glu Ala Gly Ala Val Phe Ala Glu Ile Gly Pro
Arg Met Ala 85 90 95 gag ttg agc ggt tcc cgg ctg gcc gcg cag caa
cag atg gaa ggc ctc 336 Glu Leu Ser Gly Ser Arg Leu Ala Ala Gln Gln
Gln Met Glu Gly Leu 100 105 110 ctg gcg ccg cac cgg ccc aag gag ccc
gcg tgg ttc ctg gcc acc gtc 384 Leu Ala Pro His Arg Pro Lys Glu Pro
Ala Trp Phe Leu Ala Thr Val 115 120 125 ggc gtc tcg ccc gac cac cag
ggc aag ggt ctg ggc agc gcc gtc gtg 432 Gly Val Ser Pro Asp His Gln
Gly Lys Gly Leu Gly Ser Ala Val Val 130 135 140 ctc ccc gga gtg gag
gcg gcc gag cgc gcc ggg gtg ccc gcc ttc ctg 480 Leu Pro Gly Val Glu
Ala Ala Glu Arg Ala Gly Val Pro Ala Phe Leu 145 150 155 160 gag acc
tcc gcg ccc cgc aac ctc ccc ttc tac gag cgg ctc ggc ttc 528 Glu Thr
Ser Ala Pro Arg Asn Leu Pro Phe Tyr Glu Arg Leu Gly Phe 165 170 175
acc gtc acc gcc gac gtc gag tgc ccg aag gac cgc gcg acc tgg tgc 576
Thr Val Thr Ala Asp Val Glu Cys Pro Lys Asp Arg Ala Thr Trp Cys 180
185 190 atg acc cgc aag ccc ggt gcc tga 600 Met Thr Arg Lys Pro Gly
Ala 195 113 199 PRT Artificial wt puromycin resistance gene 113 Met
Thr Glu Tyr Lys Pro Thr Val Arg Leu Ala Thr Arg Asp Asp Val 1 5 10
15 Pro Arg Ala Val Arg Thr Leu Ala Ala Ala Phe Ala Asp Tyr Pro
Ala
20 25 30 Thr Arg His Thr Val Asp Pro Asp Arg His Ile Glu Arg Val
Thr Glu 35 40 45 Leu Gln Glu Leu Phe Leu Thr Arg Val Gly Leu Asp
Ile Gly Lys Val 50 55 60 Trp Val Ala Asp Asp Gly Ala Ala Val Ala
Val Trp Thr Thr Pro Glu 65 70 75 80 Ser Val Glu Ala Gly Ala Val Phe
Ala Glu Ile Gly Pro Arg Met Ala 85 90 95 Glu Leu Ser Gly Ser Arg
Leu Ala Ala Gln Gln Gln Met Glu Gly Leu 100 105 110 Leu Ala Pro His
Arg Pro Lys Glu Pro Ala Trp Phe Leu Ala Thr Val 115 120 125 Gly Val
Ser Pro Asp His Gln Gly Lys Gly Leu Gly Ser Ala Val Val 130 135 140
Leu Pro Gly Val Glu Ala Ala Glu Arg Ala Gly Val Pro Ala Phe Leu 145
150 155 160 Glu Thr Ser Ala Pro Arg Asn Leu Pro Phe Tyr Glu Arg Leu
Gly Phe 165 170 175 Thr Val Thr Ala Asp Val Glu Cys Pro Lys Asp Arg
Ala Thr Trp Cys 180 185 190 Met Thr Arg Lys Pro Gly Ala 195 114 564
DNA Artificial wt DHFR gene (from mouse) 114 atg gtt cga cca ttg
aac tgc atc gtc gcc gtg tcc caa aat atg ggg 48 Met Val Arg Pro Leu
Asn Cys Ile Val Ala Val Ser Gln Asn Met Gly 1 5 10 15 att ggc aag
aac gga gac cta ccc tgg cct ccg ctc agg aac gag ttc 96 Ile Gly Lys
Asn Gly Asp Leu Pro Trp Pro Pro Leu Arg Asn Glu Phe 20 25 30 aag
tac ttc caa aga atg acc aca acc tct tca gtg gaa ggt aaa cag 144 Lys
Tyr Phe Gln Arg Met Thr Thr Thr Ser Ser Val Glu Gly Lys Gln 35 40
45 aat ctg gtg att atg ggt agg aaa acc tgg ttc tcc att cct gag aag
192 Asn Leu Val Ile Met Gly Arg Lys Thr Trp Phe Ser Ile Pro Glu Lys
50 55 60 aat cga cct tta aag gac aga att aat ata gtt ctc agt aga
gaa ctc 240 Asn Arg Pro Leu Lys Asp Arg Ile Asn Ile Val Leu Ser Arg
Glu Leu 65 70 75 80 aaa gaa cca cca cga gga gct cat ttt ctt gcc aaa
agt ttg gat gat 288 Lys Glu Pro Pro Arg Gly Ala His Phe Leu Ala Lys
Ser Leu Asp Asp 85 90 95 gcc tta aga ctt att gaa caa ccg gaa ttg
gca agt aaa gta gac atg 336 Ala Leu Arg Leu Ile Glu Gln Pro Glu Leu
Ala Ser Lys Val Asp Met 100 105 110 gtt tgg ata gtc gga ggc agt tct
gtt tac cag gaa gcc atg aat caa 384 Val Trp Ile Val Gly Gly Ser Ser
Val Tyr Gln Glu Ala Met Asn Gln 115 120 125 cca ggc cac ctc aga ctc
ttt gtg aca agg atc atg cag gaa ttt gaa 432 Pro Gly His Leu Arg Leu
Phe Val Thr Arg Ile Met Gln Glu Phe Glu 130 135 140 agt gac acg ttt
ttc cca gaa att gat ttg ggg aaa tat aaa ctt ctc 480 Ser Asp Thr Phe
Phe Pro Glu Ile Asp Leu Gly Lys Tyr Lys Leu Leu 145 150 155 160 cca
gaa tac cca ggc gtc ctc tct gag gtc cag gag gaa aaa ggc atc 528 Pro
Glu Tyr Pro Gly Val Leu Ser Glu Val Gln Glu Glu Lys Gly Ile 165 170
175 aag tat aag ttt gaa gtc tac gag aag aaa gac taa 564 Lys Tyr Lys
Phe Glu Val Tyr Glu Lys Lys Asp 180 185 115 187 PRT Artificial wt
DHFR gene (from mouse) 115 Met Val Arg Pro Leu Asn Cys Ile Val Ala
Val Ser Gln Asn Met Gly 1 5 10 15 Ile Gly Lys Asn Gly Asp Leu Pro
Trp Pro Pro Leu Arg Asn Glu Phe 20 25 30 Lys Tyr Phe Gln Arg Met
Thr Thr Thr Ser Ser Val Glu Gly Lys Gln 35 40 45 Asn Leu Val Ile
Met Gly Arg Lys Thr Trp Phe Ser Ile Pro Glu Lys 50 55 60 Asn Arg
Pro Leu Lys Asp Arg Ile Asn Ile Val Leu Ser Arg Glu Leu 65 70 75 80
Lys Glu Pro Pro Arg Gly Ala His Phe Leu Ala Lys Ser Leu Asp Asp 85
90 95 Ala Leu Arg Leu Ile Glu Gln Pro Glu Leu Ala Ser Lys Val Asp
Met 100 105 110 Val Trp Ile Val Gly Gly Ser Ser Val Tyr Gln Glu Ala
Met Asn Gln 115 120 125 Pro Gly His Leu Arg Leu Phe Val Thr Arg Ile
Met Gln Glu Phe Glu 130 135 140 Ser Asp Thr Phe Phe Pro Glu Ile Asp
Leu Gly Lys Tyr Lys Leu Leu 145 150 155 160 Pro Glu Tyr Pro Gly Val
Leu Ser Glu Val Gln Glu Glu Lys Gly Ile 165 170 175 Lys Tyr Lys Phe
Glu Val Tyr Glu Lys Lys Asp 180 185 116 1143 DNA Artificial wt
hygromycin resistance gene 116 atg aaa aag cct gaa ctc acc gcg acg
tct gtc gag aag ttt ctg atc 48 Met Lys Lys Pro Glu Leu Thr Ala Thr
Ser Val Glu Lys Phe Leu Ile 1 5 10 15 gaa aag ttc gac agc gtc tcc
gac ctg atg cag ctc tcg gag ggc gaa 96 Glu Lys Phe Asp Ser Val Ser
Asp Leu Met Gln Leu Ser Glu Gly Glu 20 25 30 gaa tct cgt gct ttc
agc ttc gat gta gga ggg cgt gga tat gtc ctg 144 Glu Ser Arg Ala Phe
Ser Phe Asp Val Gly Gly Arg Gly Tyr Val Leu 35 40 45 cgg gta aat
agc tgc gcc gat ggt ttc tac aaa gat cgt tat gtt tat 192 Arg Val Asn
Ser Cys Ala Asp Gly Phe Tyr Lys Asp Arg Tyr Val Tyr 50 55 60 cgg
cac ttt gca tcg gcc gcg ctc ccg att ccg gaa gtg ctt gac att 240 Arg
His Phe Ala Ser Ala Ala Leu Pro Ile Pro Glu Val Leu Asp Ile 65 70
75 80 ggg gaa ttc agc gag agc ctg acc tat tgc atc tcc cgc cgt gca
cag 288 Gly Glu Phe Ser Glu Ser Leu Thr Tyr Cys Ile Ser Arg Arg Ala
Gln 85 90 95 ggt gtc acg ttg caa gac ctg cct gaa acc gaa ctg ccc
gct gtt ctg 336 Gly Val Thr Leu Gln Asp Leu Pro Glu Thr Glu Leu Pro
Ala Val Leu 100 105 110 cag ccg gtc gcg gag gcc atg gat gcg atc gct
gcg gcc gat ctt agc 384 Gln Pro Val Ala Glu Ala Met Asp Ala Ile Ala
Ala Ala Asp Leu Ser 115 120 125 cag acg agc ggg ttc ggc cca ttc gga
ccg caa gga atc ggt caa tac 432 Gln Thr Ser Gly Phe Gly Pro Phe Gly
Pro Gln Gly Ile Gly Gln Tyr 130 135 140 act aca tgg cgt gat ttc ata
tgc gcg att gct gat ccc cat gtg tat 480 Thr Thr Trp Arg Asp Phe Ile
Cys Ala Ile Ala Asp Pro His Val Tyr 145 150 155 160 cac tgg caa act
gtg atg gac gac acc gtc agt gcg tcc gtc gcg cag 528 His Trp Gln Thr
Val Met Asp Asp Thr Val Ser Ala Ser Val Ala Gln 165 170 175 gct ctc
gat gag ctg atg ctt tgg gcc gag gac tgc ccc gaa gtc cgg 576 Ala Leu
Asp Glu Leu Met Leu Trp Ala Glu Asp Cys Pro Glu Val Arg 180 185 190
cac ctc gtg cac gcg gat ttc ggc tcc aac aat gtc ctg acg gac aat 624
His Leu Val His Ala Asp Phe Gly Ser Asn Asn Val Leu Thr Asp Asn 195
200 205 ggc cgc ata aca gcg gtc att gac tgg agc gag gcg atg ttc ggg
gat 672 Gly Arg Ile Thr Ala Val Ile Asp Trp Ser Glu Ala Met Phe Gly
Asp 210 215 220 tcc caa tac gag gtc gcc aac atc ttc ttc tgg agg ccg
tgg ttg gct 720 Ser Gln Tyr Glu Val Ala Asn Ile Phe Phe Trp Arg Pro
Trp Leu Ala 225 230 235 240 tgt atg gag cag cag acg cgc tac ttc gag
cgg agg cat ccg gag ctt 768 Cys Met Glu Gln Gln Thr Arg Tyr Phe Glu
Arg Arg His Pro Glu Leu 245 250 255 gca gga tcg ccg cgg ctc cgg gcg
tat atg ctc cgc att ggt ctt gac 816 Ala Gly Ser Pro Arg Leu Arg Ala
Tyr Met Leu Arg Ile Gly Leu Asp 260 265 270 caa ctc tat cag agc ttg
gtt gac ggc aat ttc gat gat gca gct tgg 864 Gln Leu Tyr Gln Ser Leu
Val Asp Gly Asn Phe Asp Asp Ala Ala Trp 275 280 285 gcg cag ggt cga
tgc gac gca atc gtc cga tcc gga gcc ggg act gtc 912 Ala Gln Gly Arg
Cys Asp Ala Ile Val Arg Ser Gly Ala Gly Thr Val 290 295 300 ggg cgt
aca caa atc gcc cgc aga agc gcg gcc gtc tgg acc gat ggc 960 Gly Arg
Thr Gln Ile Ala Arg Arg Ser Ala Ala Val Trp Thr Asp Gly 305 310 315
320 tgt gta gaa gta ctc gcc gat agt gga aac cga cgc ccc agc act cgt
1008 Cys Val Glu Val Leu Ala Asp Ser Gly Asn Arg Arg Pro Ser Thr
Arg 325 330 335 ccg gag gca aag gaa ttc ggg aga tgg ggg agg cta act
gaa aca cgg 1056 Pro Glu Ala Lys Glu Phe Gly Arg Trp Gly Arg Leu
Thr Glu Thr Arg 340 345 350 aag gag aca ata ccg gaa gga acc cgc gct
atg acg gca ata aaa aga 1104 Lys Glu Thr Ile Pro Glu Gly Thr Arg
Ala Met Thr Ala Ile Lys Arg 355 360 365 cag aat aaa acg cac ggg tgt
tgg gtc gtt tgt tca taa 1143 Gln Asn Lys Thr His Gly Cys Trp Val
Val Cys Ser 370 375 380 117 380 PRT Artificial wt hygromycin
resistance gene 117 Met Lys Lys Pro Glu Leu Thr Ala Thr Ser Val Glu
Lys Phe Leu Ile 1 5 10 15 Glu Lys Phe Asp Ser Val Ser Asp Leu Met
Gln Leu Ser Glu Gly Glu 20 25 30 Glu Ser Arg Ala Phe Ser Phe Asp
Val Gly Gly Arg Gly Tyr Val Leu 35 40 45 Arg Val Asn Ser Cys Ala
Asp Gly Phe Tyr Lys Asp Arg Tyr Val Tyr 50 55 60 Arg His Phe Ala
Ser Ala Ala Leu Pro Ile Pro Glu Val Leu Asp Ile 65 70 75 80 Gly Glu
Phe Ser Glu Ser Leu Thr Tyr Cys Ile Ser Arg Arg Ala Gln 85 90 95
Gly Val Thr Leu Gln Asp Leu Pro Glu Thr Glu Leu Pro Ala Val Leu 100
105 110 Gln Pro Val Ala Glu Ala Met Asp Ala Ile Ala Ala Ala Asp Leu
Ser 115 120 125 Gln Thr Ser Gly Phe Gly Pro Phe Gly Pro Gln Gly Ile
Gly Gln Tyr 130 135 140 Thr Thr Trp Arg Asp Phe Ile Cys Ala Ile Ala
Asp Pro His Val Tyr 145 150 155 160 His Trp Gln Thr Val Met Asp Asp
Thr Val Ser Ala Ser Val Ala Gln 165 170 175 Ala Leu Asp Glu Leu Met
Leu Trp Ala Glu Asp Cys Pro Glu Val Arg 180 185 190 His Leu Val His
Ala Asp Phe Gly Ser Asn Asn Val Leu Thr Asp Asn 195 200 205 Gly Arg
Ile Thr Ala Val Ile Asp Trp Ser Glu Ala Met Phe Gly Asp 210 215 220
Ser Gln Tyr Glu Val Ala Asn Ile Phe Phe Trp Arg Pro Trp Leu Ala 225
230 235 240 Cys Met Glu Gln Gln Thr Arg Tyr Phe Glu Arg Arg His Pro
Glu Leu 245 250 255 Ala Gly Ser Pro Arg Leu Arg Ala Tyr Met Leu Arg
Ile Gly Leu Asp 260 265 270 Gln Leu Tyr Gln Ser Leu Val Asp Gly Asn
Phe Asp Asp Ala Ala Trp 275 280 285 Ala Gln Gly Arg Cys Asp Ala Ile
Val Arg Ser Gly Ala Gly Thr Val 290 295 300 Gly Arg Thr Gln Ile Ala
Arg Arg Ser Ala Ala Val Trp Thr Asp Gly 305 310 315 320 Cys Val Glu
Val Leu Ala Asp Ser Gly Asn Arg Arg Pro Ser Thr Arg 325 330 335 Pro
Glu Ala Lys Glu Phe Gly Arg Trp Gly Arg Leu Thr Glu Thr Arg 340 345
350 Lys Glu Thr Ile Pro Glu Gly Thr Arg Ala Met Thr Ala Ile Lys Arg
355 360 365 Gln Asn Lys Thr His Gly Cys Trp Val Val Cys Ser 370 375
380 118 804 DNA Artificial wt neomycin resistance gene 118 atg gga
tcg gcc att gaa caa gat gga ttg cac gca ggt tct ccg gcc 48 Met Gly
Ser Ala Ile Glu Gln Asp Gly Leu His Ala Gly Ser Pro Ala 1 5 10 15
gct tgg gtg gag agg cta ttc ggc tat gac tgg gca caa cag aca atc 96
Ala Trp Val Glu Arg Leu Phe Gly Tyr Asp Trp Ala Gln Gln Thr Ile 20
25 30 ggc tgc tct gat gcc gcc gtg ttc cgg ctg tca gcg cag ggg cgc
ccg 144 Gly Cys Ser Asp Ala Ala Val Phe Arg Leu Ser Ala Gln Gly Arg
Pro 35 40 45 gtt ctt ttt gtc aag acc gac ctg tcc ggt gcc ctg aat
gaa ctg cag 192 Val Leu Phe Val Lys Thr Asp Leu Ser Gly Ala Leu Asn
Glu Leu Gln 50 55 60 gac gag gca gcg cgg cta tcg tgg ctg gcc acg
acg ggc gtt cct tgc 240 Asp Glu Ala Ala Arg Leu Ser Trp Leu Ala Thr
Thr Gly Val Pro Cys 65 70 75 80 gca gct gtg ctc gac gtt gtc act gaa
gcg gga agg gac tgg ctg cta 288 Ala Ala Val Leu Asp Val Val Thr Glu
Ala Gly Arg Asp Trp Leu Leu 85 90 95 ttg ggc gaa gtg ccg ggg cag
gat ctc ctg tca tct cac ctt gct cct 336 Leu Gly Glu Val Pro Gly Gln
Asp Leu Leu Ser Ser His Leu Ala Pro 100 105 110 gcc gag aaa gta tcc
atc atg gct gat gca atg cgg cgg ctg cat acg 384 Ala Glu Lys Val Ser
Ile Met Ala Asp Ala Met Arg Arg Leu His Thr 115 120 125 ctt gat ccg
gct acc tgc cca ttc gac cac caa gcg aaa cat cgc atc 432 Leu Asp Pro
Ala Thr Cys Pro Phe Asp His Gln Ala Lys His Arg Ile 130 135 140 gag
cga gca cgt act cgg atg gaa gcc ggt ctt gtc gat cag gat gat 480 Glu
Arg Ala Arg Thr Arg Met Glu Ala Gly Leu Val Asp Gln Asp Asp 145 150
155 160 ctg gac gaa gag cat cag ggg ctc gcg cca gcc gaa ctg ttc gcc
agg 528 Leu Asp Glu Glu His Gln Gly Leu Ala Pro Ala Glu Leu Phe Ala
Arg 165 170 175 ctc aag gcg cgc atg ccc gac ggc gat gat ctc gtc gtg
acc cat ggc 576 Leu Lys Ala Arg Met Pro Asp Gly Asp Asp Leu Val Val
Thr His Gly 180 185 190 gat gcc tgc ttg ccg aat atc atg gtg gaa aat
ggc cgc ttt tct gga 624 Asp Ala Cys Leu Pro Asn Ile Met Val Glu Asn
Gly Arg Phe Ser Gly 195 200 205 ttc atc gac tgt ggc cgg ctg ggt gtg
gcg gac cgc tat cag gac ata 672 Phe Ile Asp Cys Gly Arg Leu Gly Val
Ala Asp Arg Tyr Gln Asp Ile 210 215 220 gcg ttg gct acc cgt gat att
gct gaa gag ctt ggc ggc gaa tgg gct 720 Ala Leu Ala Thr Arg Asp Ile
Ala Glu Glu Leu Gly Gly Glu Trp Ala 225 230 235 240 gac cgc ttc ctc
gtg ctt tac ggt atc gcc gct ccc gat tcg cag cgc 768 Asp Arg Phe Leu
Val Leu Tyr Gly Ile Ala Ala Pro Asp Ser Gln Arg 245 250 255 atc gcc
ttc tat cgc ctt ctt gac gag ttc ttc tga 804 Ile Ala Phe Tyr Arg Leu
Leu Asp Glu Phe Phe 260 265 119 267 PRT Artificial wt neomycin
resistance gene 119 Met Gly Ser Ala Ile Glu Gln Asp Gly Leu His Ala
Gly Ser Pro Ala 1 5 10 15 Ala Trp Val Glu Arg Leu Phe Gly Tyr Asp
Trp Ala Gln Gln Thr Ile 20 25 30 Gly Cys Ser Asp Ala Ala Val Phe
Arg Leu Ser Ala Gln Gly Arg Pro 35 40 45 Val Leu Phe Val Lys Thr
Asp Leu Ser Gly Ala Leu Asn Glu Leu Gln 50 55 60 Asp Glu Ala Ala
Arg Leu Ser Trp Leu Ala Thr Thr Gly Val Pro Cys 65 70 75 80 Ala Ala
Val Leu Asp Val Val Thr Glu Ala Gly Arg Asp Trp Leu Leu 85 90 95
Leu Gly Glu Val Pro Gly Gln Asp Leu Leu Ser Ser His Leu Ala Pro 100
105 110 Ala Glu Lys Val Ser Ile Met Ala Asp Ala Met Arg Arg Leu His
Thr 115 120 125 Leu Asp Pro Ala Thr Cys Pro Phe Asp His Gln Ala Lys
His Arg Ile 130 135 140 Glu Arg Ala Arg Thr Arg Met Glu Ala Gly Leu
Val Asp Gln Asp Asp 145 150 155 160 Leu Asp Glu Glu His Gln Gly Leu
Ala Pro Ala Glu Leu Phe Ala Arg 165 170 175 Leu Lys Ala Arg Met Pro
Asp Gly Asp Asp Leu Val Val Thr His Gly 180 185 190 Asp Ala Cys Leu
Pro Asn Ile Met Val Glu Asn Gly Arg Phe Ser Gly 195 200 205 Phe Ile
Asp Cys Gly Arg Leu Gly Val Ala Asp Arg Tyr Gln Asp Ile 210 215 220
Ala Leu Ala Thr Arg Asp Ile Ala Glu Glu Leu Gly Gly Glu Trp Ala 225
230 235 240 Asp Arg Phe Leu Val Leu Tyr Gly Ile Ala Ala Pro Asp Ser
Gln Arg 245 250 255 Ile Ala Phe Tyr Arg Leu Leu Asp Glu Phe Phe 260
265 120 1121 DNA Artificial wt glutamine synthase gene (human) 120
atg acc acc tca gca agt tcc cac tta aat aaa ggc atc aag cag gtg 48
Met Thr Thr Ser Ala Ser Ser His Leu Asn Lys Gly Ile Lys Gln Val 1 5
10 15 tac atg tcc ctg cct cag ggt
gag aaa gtc cag gcc atg tat atc tgg 96 Tyr Met Ser Leu Pro Gln Gly
Glu Lys Val Gln Ala Met Tyr Ile Trp 20 25 30 atc gat ggt act gga
gaa gga ctg cgc tgc aag acc cgg acc ctg gac 144 Ile Asp Gly Thr Gly
Glu Gly Leu Arg Cys Lys Thr Arg Thr Leu Asp 35 40 45 agt gag ccc
aag tgt gtg gaa gag ttg cct gag tgg aat ttc gat ggc 192 Ser Glu Pro
Lys Cys Val Glu Glu Leu Pro Glu Trp Asn Phe Asp Gly 50 55 60 tcc
agt act tta cag tct gag ggt tcc aac agt gac atg tat ctc gtg 240 Ser
Ser Thr Leu Gln Ser Glu Gly Ser Asn Ser Asp Met Tyr Leu Val 65 70
75 80 cct gct gcc atg ttt cgg gac ccc ttc cgt aag gac cct aac aag
ctg 288 Pro Ala Ala Met Phe Arg Asp Pro Phe Arg Lys Asp Pro Asn Lys
Leu 85 90 95 gtg tta tgt gaa gtt ttc aag tac aat cga agg cct gca
gag acc aat 336 Val Leu Cys Glu Val Phe Lys Tyr Asn Arg Arg Pro Ala
Glu Thr Asn 100 105 110 ttg agg cac acc tgt aaa cgg ata atg gac atg
gtg agc aac cag cac 384 Leu Arg His Thr Cys Lys Arg Ile Met Asp Met
Val Ser Asn Gln His 115 120 125 ccc tgg ttt ggc atg gag cag gag tat
acc ctc atg ggg aca gat ggg 432 Pro Trp Phe Gly Met Glu Gln Glu Tyr
Thr Leu Met Gly Thr Asp Gly 130 135 140 cac ccc ttt ggt tgg cct tcc
aac ggc ttc cca ggg ccc cag ggt cca 480 His Pro Phe Gly Trp Pro Ser
Asn Gly Phe Pro Gly Pro Gln Gly Pro 145 150 155 160 tat tac tgt ggt
gtg gga gca gac aga gcc tat ggc agg gac atc gtg 528 Tyr Tyr Cys Gly
Val Gly Ala Asp Arg Ala Tyr Gly Arg Asp Ile Val 165 170 175 gag gcc
cat tac cgg gcc tgc ttg tat gct gga gtc aag att gcg ggg 576 Glu Ala
His Tyr Arg Ala Cys Leu Tyr Ala Gly Val Lys Ile Ala Gly 180 185 190
act aat gcc gag gtc atg cct gcc cag tgg gaa ttt cag att gga cct 624
Thr Asn Ala Glu Val Met Pro Ala Gln Trp Glu Phe Gln Ile Gly Pro 195
200 205 tgt gaa gga atc agc atg gga gat cat ctc tgg gtg gcc cgt ttc
atc 672 Cys Glu Gly Ile Ser Met Gly Asp His Leu Trp Val Ala Arg Phe
Ile 210 215 220 ttg cat cgt gtg tgt gaa gac ttt gga gtg ata gca acc
ttt gat cct 720 Leu His Arg Val Cys Glu Asp Phe Gly Val Ile Ala Thr
Phe Asp Pro 225 230 235 240 aag ccc att cct ggg aac tgg aat ggt gca
ggc tgc cat acc aac ttc 768 Lys Pro Ile Pro Gly Asn Trp Asn Gly Ala
Gly Cys His Thr Asn Phe 245 250 255 agc acc aag gcc atg cgg gag gag
aat ggt ctg aag tac atc gag gag 816 Ser Thr Lys Ala Met Arg Glu Glu
Asn Gly Leu Lys Tyr Ile Glu Glu 260 265 270 gcc att gag aaa cta agc
aag cgg cac cag tac cac atc cgt gcc tat 864 Ala Ile Glu Lys Leu Ser
Lys Arg His Gln Tyr His Ile Arg Ala Tyr 275 280 285 gat ccc aag gga
ggc ctg gac aat gcc cga cgt cta act gga ttc cat 912 Asp Pro Lys Gly
Gly Leu Asp Asn Ala Arg Arg Leu Thr Gly Phe His 290 295 300 gaa acc
tcc aac atc aac gac ttt tct ggt ggt gta gcc aat cgt agc 960 Glu Thr
Ser Asn Ile Asn Asp Phe Ser Gly Gly Val Ala Asn Arg Ser 305 310 315
320 gcc agc ata cgc att ccc cgg act gtt ggc cag gag aag aag ggt tac
1008 Ala Ser Ile Arg Ile Pro Arg Thr Val Gly Gln Glu Lys Lys Gly
Tyr 325 330 335 ttt gaa gat cgt cgc ccc tct gcc aac tgc gac ccc ttt
tcg gtg aca 1056 Phe Glu Asp Arg Arg Pro Ser Ala Asn Cys Asp Pro
Phe Ser Val Thr 340 345 350 gaa gcc ctc atc cgc acg tgt ctt ctc aat
gaa acc ggc gat gag ccc 1104 Glu Ala Leu Ile Arg Thr Cys Leu Leu
Asn Glu Thr Gly Asp Glu Pro 355 360 365 ttc cag tac aaa aat ta 1121
Phe Gln Tyr Lys Asn 370 121 373 PRT Artificial wt glutamine
synthase gene (human) 121 Met Thr Thr Ser Ala Ser Ser His Leu Asn
Lys Gly Ile Lys Gln Val 1 5 10 15 Tyr Met Ser Leu Pro Gln Gly Glu
Lys Val Gln Ala Met Tyr Ile Trp 20 25 30 Ile Asp Gly Thr Gly Glu
Gly Leu Arg Cys Lys Thr Arg Thr Leu Asp 35 40 45 Ser Glu Pro Lys
Cys Val Glu Glu Leu Pro Glu Trp Asn Phe Asp Gly 50 55 60 Ser Ser
Thr Leu Gln Ser Glu Gly Ser Asn Ser Asp Met Tyr Leu Val 65 70 75 80
Pro Ala Ala Met Phe Arg Asp Pro Phe Arg Lys Asp Pro Asn Lys Leu 85
90 95 Val Leu Cys Glu Val Phe Lys Tyr Asn Arg Arg Pro Ala Glu Thr
Asn 100 105 110 Leu Arg His Thr Cys Lys Arg Ile Met Asp Met Val Ser
Asn Gln His 115 120 125 Pro Trp Phe Gly Met Glu Gln Glu Tyr Thr Leu
Met Gly Thr Asp Gly 130 135 140 His Pro Phe Gly Trp Pro Ser Asn Gly
Phe Pro Gly Pro Gln Gly Pro 145 150 155 160 Tyr Tyr Cys Gly Val Gly
Ala Asp Arg Ala Tyr Gly Arg Asp Ile Val 165 170 175 Glu Ala His Tyr
Arg Ala Cys Leu Tyr Ala Gly Val Lys Ile Ala Gly 180 185 190 Thr Asn
Ala Glu Val Met Pro Ala Gln Trp Glu Phe Gln Ile Gly Pro 195 200 205
Cys Glu Gly Ile Ser Met Gly Asp His Leu Trp Val Ala Arg Phe Ile 210
215 220 Leu His Arg Val Cys Glu Asp Phe Gly Val Ile Ala Thr Phe Asp
Pro 225 230 235 240 Lys Pro Ile Pro Gly Asn Trp Asn Gly Ala Gly Cys
His Thr Asn Phe 245 250 255 Ser Thr Lys Ala Met Arg Glu Glu Asn Gly
Leu Lys Tyr Ile Glu Glu 260 265 270 Ala Ile Glu Lys Leu Ser Lys Arg
His Gln Tyr His Ile Arg Ala Tyr 275 280 285 Asp Pro Lys Gly Gly Leu
Asp Asn Ala Arg Arg Leu Thr Gly Phe His 290 295 300 Glu Thr Ser Asn
Ile Asn Asp Phe Ser Gly Gly Val Ala Asn Arg Ser 305 310 315 320 Ala
Ser Ile Arg Ile Pro Arg Thr Val Gly Gln Glu Lys Lys Gly Tyr 325 330
335 Phe Glu Asp Arg Arg Pro Ser Ala Asn Cys Asp Pro Phe Ser Val Thr
340 345 350 Glu Ala Leu Ile Arg Thr Cys Leu Leu Asn Glu Thr Gly Asp
Glu Pro 355 360 365 Phe Gln Tyr Lys Asn 370 122 43 DNA Artificial
primer GTGspaceBamHIF 122 gaattcggat ccaccgtggc gatccaaaga
ctgccaaatc tag 43 123 42 DNA Artificial primer ZEOTTTGTGBamHIF 123
gaattcggat cctttgtggc caagttgacc agtgccgttc cg 42 124 46 DNA
Artificial primer ZEOForwardGTG-Thr9 124 aattggatcc accgtggcca
agttgaccag tgccgttacc gtgctc 46 125 46 DNA Artificial pimer
ZEOForward GTG-Phe9 125 aattggatcc accgtggcca agttgaccag tgccgttttc
gtgctc 46 126 43 DNA Artificial primer TTGspaceBamHIF 126
gaattcggat ccaccttggc gatccaaaga ctgccaaatc tag 43 127 46 DNA
Artificial primer ZEOForwardTTG-Thr9 127 aattggatcc accttggcca
agttgaccag tgccgttacc gtgctc 46 128 46 DNA Artificial pimer
ZEOForwardTTG-Phe9 128 aattggatcc accttggcca agttgaccag tgccgttttc
gtgctc 46 129 37 DNA Artificial primer PURO BamHI F 129 gatcggatcc
atggttaccg agtacaagcc cacggtg 37 130 35 DNA Artificial primer
PURO300 R LEU 130 cagccgggaa ccgctcaact cggccaggcg cgggc 35 131 49
DNA Artificial primer PURO300FLEU 131 cgagttgagc ggttcccggc
tggccgcgca gcaacagctg gaaggcctc 49 132 44 DNA Artificial primer
PURO600RLEU 132 aagcttgaat tcaggcaccg ggcttgcggg tcaggcacca ggtc 44
133 42 DNA Artificial primer PUROBamHI TTG1F 133 gaattcggat
ccaccttggt taccgagtac aagcccacgg tg 42 134 804 DNA Artificial
modified neomycin resistance gene lacking internal ATG sequences
134 atg gga tcg gcc att gaa caa gac gga ttg cac gca ggt tct ccg gcc
48 Met Gly Ser Ala Ile Glu Gln Asp Gly Leu His Ala Gly Ser Pro Ala
1 5 10 15 gct tgg gtg gag agg cta ttc ggc tac gac tgg gca caa cag
aca atc 96 Ala Trp Val Glu Arg Leu Phe Gly Tyr Asp Trp Ala Gln Gln
Thr Ile 20 25 30 ggc tgc tct gac gcc gcc gtg ttc cgg ctg tca gcg
cag ggg cgc ccg 144 Gly Cys Ser Asp Ala Ala Val Phe Arg Leu Ser Ala
Gln Gly Arg Pro 35 40 45 gtt ctt ttt gtc aag acc gac ctg tcc ggt
gcc ctg aac gaa ctg cag 192 Val Leu Phe Val Lys Thr Asp Leu Ser Gly
Ala Leu Asn Glu Leu Gln 50 55 60 gac gag gca gcg cgg cta tcg tgg
ctg gcc acg acg ggc gtt cct tgc 240 Asp Glu Ala Ala Arg Leu Ser Trp
Leu Ala Thr Thr Gly Val Pro Cys 65 70 75 80 gca gct gtg ctc gac gtt
gtc act gaa gcg gga agg gac tgg ctg cta 288 Ala Ala Val Leu Asp Val
Val Thr Glu Ala Gly Arg Asp Trp Leu Leu 85 90 95 ttg ggc gaa gtg
ccg ggg cag gat ctc ctg tca tct cac ctt gct cct 336 Leu Gly Glu Val
Pro Gly Gln Asp Leu Leu Ser Ser His Leu Ala Pro 100 105 110 gcc gag
aaa gta tcc atc ctg gct gac gca ctg cgg cgg ctg cat acg 384 Ala Glu
Lys Val Ser Ile Leu Ala Asp Ala Leu Arg Arg Leu His Thr 115 120 125
ctt gat ccg gct acc tgc cca ttc gac cac caa gcg aaa cat cgc atc 432
Leu Asp Pro Ala Thr Cys Pro Phe Asp His Gln Ala Lys His Arg Ile 130
135 140 gag cga gca cgt act cgg ctg gaa gcc ggt ctt gtc gat cag gac
gat 480 Glu Arg Ala Arg Thr Arg Leu Glu Ala Gly Leu Val Asp Gln Asp
Asp 145 150 155 160 ctg gac gaa gag cat cag ggg ctc gcg cca gcc gaa
ctg ttc gcc agg 528 Leu Asp Glu Glu His Gln Gly Leu Ala Pro Ala Glu
Leu Phe Ala Arg 165 170 175 ctc aag gcg cgc ctg ccc gac ggc gac gat
ctc gtc gtg acc cac ggc 576 Leu Lys Ala Arg Leu Pro Asp Gly Asp Asp
Leu Val Val Thr His Gly 180 185 190 gac gcc tgc ttg ccg aat atc ctg
gtg gaa aac ggc cgc ttt tct gga 624 Asp Ala Cys Leu Pro Asn Ile Leu
Val Glu Asn Gly Arg Phe Ser Gly 195 200 205 ttc atc gac tgt ggc cgg
ctg ggt gtg gcg gac cgc tat cag gac ata 672 Phe Ile Asp Cys Gly Arg
Leu Gly Val Ala Asp Arg Tyr Gln Asp Ile 210 215 220 gcg ttg gct acc
cgt gat att gct gaa gag ctt ggc ggc gag tgg gct 720 Ala Leu Ala Thr
Arg Asp Ile Ala Glu Glu Leu Gly Gly Glu Trp Ala 225 230 235 240 gac
cgc ttc ctc gtg ctt tac ggt atc gcc gct ccc gat tcg cag cgc 768 Asp
Arg Phe Leu Val Leu Tyr Gly Ile Ala Ala Pro Asp Ser Gln Arg 245 250
255 atc gcc ttc tat cgc ctt ctt gac gag ttc ttc tga 804 Ile Ala Phe
Tyr Arg Leu Leu Asp Glu Phe Phe 260 265 135 267 PRT Artificial
modified neomycin resistance gene lacking internal ATG sequences
135 Met Gly Ser Ala Ile Glu Gln Asp Gly Leu His Ala Gly Ser Pro Ala
1 5 10 15 Ala Trp Val Glu Arg Leu Phe Gly Tyr Asp Trp Ala Gln Gln
Thr Ile 20 25 30 Gly Cys Ser Asp Ala Ala Val Phe Arg Leu Ser Ala
Gln Gly Arg Pro 35 40 45 Val Leu Phe Val Lys Thr Asp Leu Ser Gly
Ala Leu Asn Glu Leu Gln 50 55 60 Asp Glu Ala Ala Arg Leu Ser Trp
Leu Ala Thr Thr Gly Val Pro Cys 65 70 75 80 Ala Ala Val Leu Asp Val
Val Thr Glu Ala Gly Arg Asp Trp Leu Leu 85 90 95 Leu Gly Glu Val
Pro Gly Gln Asp Leu Leu Ser Ser His Leu Ala Pro 100 105 110 Ala Glu
Lys Val Ser Ile Leu Ala Asp Ala Leu Arg Arg Leu His Thr 115 120 125
Leu Asp Pro Ala Thr Cys Pro Phe Asp His Gln Ala Lys His Arg Ile 130
135 140 Glu Arg Ala Arg Thr Arg Leu Glu Ala Gly Leu Val Asp Gln Asp
Asp 145 150 155 160 Leu Asp Glu Glu His Gln Gly Leu Ala Pro Ala Glu
Leu Phe Ala Arg 165 170 175 Leu Lys Ala Arg Leu Pro Asp Gly Asp Asp
Leu Val Val Thr His Gly 180 185 190 Asp Ala Cys Leu Pro Asn Ile Leu
Val Glu Asn Gly Arg Phe Ser Gly 195 200 205 Phe Ile Asp Cys Gly Arg
Leu Gly Val Ala Asp Arg Tyr Gln Asp Ile 210 215 220 Ala Leu Ala Thr
Arg Asp Ile Ala Glu Glu Leu Gly Gly Glu Trp Ala 225 230 235 240 Asp
Arg Phe Leu Val Leu Tyr Gly Ile Ala Ala Pro Asp Ser Gln Arg 245 250
255 Ile Ala Phe Tyr Arg Leu Leu Asp Glu Phe Phe 260 265 136 40 DNA
Artificial primer NEO-F-HindIII 136 gatcaagctt ttggatcggc
cattgaaaca agacggattg 40 137 36 DNA Artificial primer NEO EcoRI
800R 137 aagcttgaat tctcagaaga actcgtcaag aaggcg 36 138 564 DNA
Artificial modified dhfr gene lacking internal ATG sequences 138
atg gtt cga cca ttg aac tgc atc gtc gcc gtg tcc caa aat ctg ggg 48
Met Val Arg Pro Leu Asn Cys Ile Val Ala Val Ser Gln Asn Leu Gly 1 5
10 15 att ggc aag aac gga gac cta ccc tgg cct ccg ctc agg aac gag
ttc 96 Ile Gly Lys Asn Gly Asp Leu Pro Trp Pro Pro Leu Arg Asn Glu
Phe 20 25 30 aag tac ttc caa aga ctg acc aca acc tct tca gtg gaa
ggt aaa cag 144 Lys Tyr Phe Gln Arg Leu Thr Thr Thr Ser Ser Val Glu
Gly Lys Gln 35 40 45 aat ctg gtg att ctg ggt agg aaa acc tgg ttc
tcc att cct gag aag 192 Asn Leu Val Ile Leu Gly Arg Lys Thr Trp Phe
Ser Ile Pro Glu Lys 50 55 60 aat cga cct tta aag gac aga att aat
ata gtt ctc agt aga gaa ctc 240 Asn Arg Pro Leu Lys Asp Arg Ile Asn
Ile Val Leu Ser Arg Glu Leu 65 70 75 80 aaa gaa cca cca cga gga gct
cat ttt ctt gcc aaa agt ttg gac gac 288 Lys Glu Pro Pro Arg Gly Ala
His Phe Leu Ala Lys Ser Leu Asp Asp 85 90 95 gcc tta aga ctt att
gaa caa ccg gaa ttg gca agt aaa gta gac ctg 336 Ala Leu Arg Leu Ile
Glu Gln Pro Glu Leu Ala Ser Lys Val Asp Leu 100 105 110 gtt tgg ata
gtc gga ggc agt tct gtt tac cag gaa gcc ctg aat caa 384 Val Trp Ile
Val Gly Gly Ser Ser Val Tyr Gln Glu Ala Leu Asn Gln 115 120 125 cca
ggc cac ctc aga ctc ttt gtg aca agg att ctg cag gaa ttt gaa 432 Pro
Gly His Leu Arg Leu Phe Val Thr Arg Ile Leu Gln Glu Phe Glu 130 135
140 agt gac acg ttt ttc cca gaa att gat ttg ggg aaa tat aaa ctt ctc
480 Ser Asp Thr Phe Phe Pro Glu Ile Asp Leu Gly Lys Tyr Lys Leu Leu
145 150 155 160 cca gaa tac cca ggc gtc ctc tct gag gtc cag gag gaa
aaa ggc atc 528 Pro Glu Tyr Pro Gly Val Leu Ser Glu Val Gln Glu Glu
Lys Gly Ile 165 170 175 aag tat aag ttt gaa gtc tac gag aag aaa gac
taa 564 Lys Tyr Lys Phe Glu Val Tyr Glu Lys Lys Asp 180 185 139 187
PRT Artificial modified dhfr gene lacking internal ATG sequences
139 Met Val Arg Pro Leu Asn Cys Ile Val Ala Val Ser Gln Asn Leu Gly
1 5 10 15 Ile Gly Lys Asn Gly Asp Leu Pro Trp Pro Pro Leu Arg Asn
Glu Phe 20 25 30 Lys Tyr Phe Gln Arg Leu Thr Thr Thr Ser Ser Val
Glu Gly Lys Gln 35 40 45 Asn Leu Val Ile Leu Gly Arg Lys Thr Trp
Phe Ser Ile Pro Glu Lys 50 55 60 Asn Arg Pro Leu Lys Asp Arg Ile
Asn Ile Val Leu Ser Arg Glu Leu 65 70 75 80 Lys Glu Pro Pro Arg Gly
Ala His Phe Leu Ala Lys Ser Leu Asp Asp 85 90 95 Ala Leu Arg Leu
Ile Glu Gln Pro Glu Leu Ala Ser Lys Val Asp Leu 100 105 110 Val Trp
Ile Val Gly Gly Ser Ser Val Tyr Gln Glu Ala Leu Asn Gln 115 120 125
Pro Gly His Leu Arg Leu Phe Val Thr Arg Ile Leu Gln Glu Phe Glu 130
135 140 Ser Asp Thr Phe Phe Pro Glu Ile Asp Leu Gly Lys Tyr Lys Leu
Leu 145 150 155 160 Pro Glu Tyr Pro Gly Val Leu Ser Glu Val Gln Glu
Glu Lys Gly Ile 165 170 175 Lys Tyr Lys Phe Glu Val Tyr Glu Lys Lys
Asp 180 185 140 36 DNA Artificial primer DHFR-F-HindIII 140
gatcaagctt ttgttcgacc attgaactgc atcgtc
36 141 36 DNA Artificial primer DHFR-EcoRI-600-R 141 aagcttgaat
tcttagtctt tcttctcgta gacttc 36 142 154 DNA Artificial combined
synthetic polyadenylation sequence and pausing signal from the
human alpha2 globin gene 142 aataaaatat ctttattttc attacatctg
tgtgttggtt ttttgtgtga atcgatagta 60 ctaacatacg ctctccatca
aaacaaaacg aaacaaaaca aactagcaaa ataggctgtc 120 cccagtgcaa
gtgcaggtgc cagaacattt ctct 154
* * * * *