U.S. patent application number 13/092770 was filed with the patent office on 2014-05-15 for methods of modulating smyd3 for treatment of cancer.
This patent application is currently assigned to Oncotherapy Science, Inc.. The applicant listed for this patent is Yoichi Furukawa, Ryuji Hamamoto, Yusuke Nakamura, Shuichi Nakatsuru. Invention is credited to Yoichi Furukawa, Ryuji Hamamoto, Yusuke Nakamura, Shuichi Nakatsuru.
Application Number | 20140134637 13/092770 |
Document ID | / |
Family ID | 37453072 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140134637 |
Kind Code |
A1 |
Nakamura; Yusuke ; et
al. |
May 15, 2014 |
METHODS OF MODULATING SMYD3 FOR TREATMENT OF CANCER
Abstract
The present invention features a method for determining the
methyltransferase activity of a polypeptide and screening for
modulators of methyltransferase activity, more particularly for
modulators of the methylation of retinoblastoma by SMYD3. The
invention further provides a method or pharmaceutical composition
for prevention or treating of colorectal cancer, hepatocellular
carcinoma, bladder cancer and/or breast cancer using a modulator so
identified.
Inventors: |
Nakamura; Yusuke; (Tokyo,
JP) ; Furukawa; Yoichi; (Tokyo, JP) ;
Hamamoto; Ryuji; (Tokyo, JP) ; Nakatsuru;
Shuichi; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nakamura; Yusuke
Furukawa; Yoichi
Hamamoto; Ryuji
Nakatsuru; Shuichi |
Tokyo
Tokyo
Tokyo
Kanagawa |
|
JP
JP
JP
JP |
|
|
Assignee: |
Oncotherapy Science, Inc.
Kanagawa
JP
|
Family ID: |
37453072 |
Appl. No.: |
13/092770 |
Filed: |
April 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11912860 |
Dec 23, 2008 |
7968281 |
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PCT/JP2006/313038 |
Jun 23, 2006 |
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13092770 |
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60695957 |
Jul 1, 2005 |
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Current U.S.
Class: |
435/7.1 |
Current CPC
Class: |
G01N 2333/4736 20130101;
G01N 33/5011 20130101; G01N 2333/91011 20130101; C12Y 201/01043
20130101; G01N 2500/02 20130101; G01N 33/57407 20130101; A61P 35/00
20180101; C12Q 1/48 20130101 |
Class at
Publication: |
435/7.1 |
International
Class: |
G01N 33/50 20060101
G01N033/50 |
Claims
1.-6. (canceled)
7. A method of screening for a compound for treating a cancer
selected from group consisting of colorectal cancer, hepatocellular
carcinoma, bladder cancer, and breast cancer, said method
comprising the steps of: a. identifying a test compound that
modulates methylation of a retinoblastoma peptide by SMYD3
according to a method comprising the steps of: 1) contacting an
SMYD3 polypeptide having a methyltransferase activity selected from
the group consisting of: i. a polypeptide comprising the amino acid
sequence of SEQ ID NO: 2; ii. a polypeptide that comprises the
amino acid sequence of positions 117 to 246 of the amino acid
sequence of SEQ ID NO: 2, wherein said polypeptide has a
methyltransferase activity equivalent to the polypeptide consisting
of the amino acid sequence of SEQ ID NO: 2; iii. a polypeptide that
comprises the amino acid sequence of positions 1 to 250 of the
amino acid sequence of SEQ ID NO: 2; vi. a polypeptide that
comprises the amino acid sequence of positions 45 to 428 of the
amino acid sequence of SEQ ID NO: 2; v. a polypeptide that
comprises the amino acid sequence of SEQ ID NO: 2 in which the
amino acids of positions 1 to 30 have been deleted; vi. a
polypeptide that comprises the amino acid sequence of SEQ ID NO: 2
in which the amino acids of positions 1 to 44 are deleted; vii. a
polypeptide that comprises the amino acid sequence of SEQ ID NO: 2
in which the amino acids of positions 1 to 20 are deleted; viii. a
polypeptide that comprises the amino acid sequence of SEQ ID NO: 2
in which the amino acids of positions 1 to 10 are deleted; with a
retinoblastoma peptide to be methylated and a cofactor in the
presence of the test compound under conditions suitable for
methylation of the retinoblastoma peptide; 2) detecting the
methylation level of the retinoblastoma peptide; and 3) comparing
the methylation level of step 2) with a control level detected in
the absence of the test compound, and b. selecting the test
compound that decreases the methylation level of the retinoblastoma
peptide to be methylated as compared to a control methylation level
detected in the absence of the test compound.
8.-21. (canceled)
22. The method of claim 7, wherein the retinoblastoma peptide
comprises the amino acid sequence of SEQ ID NO: 4, or a functional
mutant comprising the amino acid sequence of SEQ ID NO: 4,
including one or more of the following mutations: K889A, K896A,
K791A, K814A, K791A and K824A, and K814A and K824A, or is a
functional fragment consisting of the amino acid sequence of
positions 769-921 of the amino acid sequence of SEQ ID NO: 4.
23. The method of claim 7, wherein said cofactor is S-adenosyl
homocysteine hydrolase (SAHH).
Description
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 60/695,957 filed Jul. 1, 2005, the contents of
which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to transcriptional regulation,
more particularly to the identification of agents that modulate
methyltransferase activity, such as agents that modulate
methylation of retinoblastoma by SMYD3 (also known as "ZNFN3A1").
As SMYD3 is up-regulated in a number of cancer types, SMYD3
modulators so identified may prove useful in the treatment of
cancer, including, for example, colorectal carcinoma,
hepatocellular carcinoma, breast cancer and bladder cancer.
BACKGROUND ART
[0003] Recent molecular studies have disclosed that abrogated cell
cycle control underlies a wide range of human tumors (Sherr, C. J.,
Science 274, 1672-7 (1996)). Genetic alteration in p53, RB1, or p16
genes is involved in a great majority of human cancers, where
deregulated cell cycle progression results in uncontrolled cell
proliferation (Hanahan, D. & Weinberg, R. A. Cell 100, 57-70
(2000); Sherr, C. J. & McCormick, F. Cancer Cell 2, 103-12
(2002)). Among the cell cycling, the G.sub.1/S boundary, wherein
cell cycle is arrested, integrity of the genome is surveyed, and
DNA damages are repaired, is critical for the maintenance of normal
cellular and genomic properties. Two key signaling pathways, namely
p53 and RB1, participate in the regulation of the G.sub.1/S
boundary by controlling a number of downstream genes. Cells
containing damaged DNA are arrested at this boundary by the
induction p21.sup.Cip1 through transactivation of accumulated wild
type p53 protein (Sherr, C. J. & Roberts, J. M. Genes Dev 13,
1501-12 (1999)). Isolated as a responsible gene for familial
retinoblastoma (Friend, S. H. et al. Nature 323, 643-6 (1986);
Fung, Y. K. et al. Science 236, 1657-61 (1987); Lee, W. H. et al.
Science 235, 1394-9 (1987)), RB1 functions as a tumor suppressor
through the control of cell cycle progression. From the G.sub.1 to
the S cell cycle transition, RB1 is inactivated by phosphorylation,
which is catalyzed by cyclin dependent kinases (CDKs). Under
phosphorylated RB1 inhibits the activator E2Fs, transcription
factors that modulate expression of genes required for DNA
replication and cell cycle progression (Dannenberg, J. H., et al.,
Genes Dev 14, 3051-64 (2000); Sage, J. et al. Genes Dev 14, 3037-50
(2000)), by a direct interaction with their activation domain,
alteration of chromatin structure complexed with HDACs, and
recruitment of a repressor complex to E2F-binding site(s) in the
promoter region of responsive genes (Weintraub, S. J., et al.,
Nature 358, 259-61 (1992); Sellers, W. R., et al., Proc Natl Acad
Sci USA 92, 11544-8 (1995)). Phosphorylated by CDK/cyclin
complexes, such as CDK4/cyclinD, RB1 dissociates E2Fs, which then
transactivate downstream genes including cyclin E, c-Myb, CDK2, and
BCL2.
[0004] The present inventors previously reported that SMYD3 has a
di- and tri-methyltransferase activity on lysine 4 of histone H3
(H3-K4), and that elevated SMYD3 expression plays a crucial role in
the proliferation of colorectal carcinoma (CRC) and hepatocellular
carcinoma (HCC) cells (Hamamoto, R. et al., Nat Cell Biol 6, 731-40
(2004)), because over-expression of SMYD3 resulted in growth
promotion of NIH3T3 cells and the knockdown of endogenous SMYD3
expression in several cancer cells induced a growth inhibition and
apoptosis of those cells. However, the precise mechanism(s) by
which SMYD3-overexpression results in growth promotion remains
unresolved. Modification of histones by acetylation,
phosphorylation, and/or methylation regulates chromatin structure
that leads to transcriptional activation or inactivation of target
gene(s) by recruiting different molecules. Regarding histone lysine
methylation, modification of H3-K4, H3-K36, and H3-K79 is
associated with a transcriptional activation by the conformational
change from heterochromatin to euchromatin structure (Im, H. et
al., J Biol Chem 278, 18346-52 (2003); Bannister, A. J. et al., J
Biol Chem 280, 17732-6 (2005); Schneider, R. et al., Nat Cell Biol
6, 73-7 (2004)), whereas methylation of H3-K9, H3-K27, and H4-K20
results in transcriptional repression by heterochromatin structure
(Schotta, G. et al., Genes Dev 18, 1251-62 (2004); Nakayama, J. et
al., Science 292, 110-3 (2001); Kirmizis, A. et al. Genes Dev 18,
1592-605 (2004)).
SUMMARY OF THE INVENTION
[0005] The present invention is based, at least in part, on the
discovery of a novel mechanism of RB1 regulation through lysine 824
methylation by SMYD3. SMYD3, also known under the gene name
"ZNFN3A1", is a histone H3 methyltransferase that is up-regulated
in a great majority of colorectal and hepatocellular carcinomas
(See, for example, WO 2003/027413) as well as bladder and breast
cancers.
[0006] The C-terminal region of RB1 interacts with the SET domain
of SMYD3. Furthermore, expression of SMYD3 enhanced the
phosphorylation of 821/826 and 807/811 of RB1 by CDK2/cyclinE or
CDK6/cyclinD3 complex in vitro and in vivo, which, in turn,
resulted in augmented transcriptional activity of E2F in HEK293
cells. This data implies that enhanced SMYD3 expression promotes
cell cycle progression through the modification of RB1 and
subsequent transcriptional activation of E2F in cancer cells. The
instant findings suggest a novel mechanism underlying the
regulation of RB1. In addition, the present findings contribute to
the better understanding of carcinogenesis, more particularly
colorectal, hepatocellular, bladder and breast carcinogenesis, and
thus contribute to the development new therapeutic strategies for
these tumors. [0007] Accordingly, it is an object of the present
invention to provide a method for identifying an agent that
modulates methylation of retinoblastoma by SMYD3, the method
including the steps of: [0008] (a) contacting an SMYD3 polypeptide
having a methyltransferase activity with a retinoblastoma peptide
to be methylated and a cofactor in the presence of a test agent
under conditions suitable for the methylation of the retinoblastoma
peptide; [0009] (b) detecting the methylation level of the
retinoblastoma peptide; and [0010] (c) comparing the methylation
level detected in step (b) with a control level detected in the
absence of the agent [0011] wherein an increase or decrease in the
methylation level as compared to the control level indicates that
the agent modulates methylation of retinoblastoma by SMYD3. [0012]
It is a further object of the present invention to provide a kit
for detecting for the ability of a test compound to regulate
methylation of retinoblastoma, such a kit including (a) an SMYD3
polypeptide having methyl transferase activity, (b) a
retinoblastoma peptide capable of being methylated by the SMYD3
polypeptide, and (c) a cofactor for the methylation of the
retinoblastoma peptide. In a further embodiment, the kit may
optionally include S-adenosyl homocysteine hydrolase (SAHH).
[0013] The present invention further provides a method of screening
for a compound for treating a cancer, such as colorectal cancer,
hepatocellular carcinoma, bladder cancer, and breast cancer, such a
method including the steps of: (a) identifying a test compound that
modulates methylation according to the method described above, and
(b) selecting the test compound that decreases the methylation
level of the substrate to be methylated as compared to a control
methylation level detected in the absence of the test compound.
[0014] The present invention further provides a composition for
alleviating a symptom of a cancer, such as colorectal cancer,
hepatocellular carcinoma, bladder cancer, and breast cancer, such
composition composed of a pharmaceutically effective amount of a
compound identified by the method described above and a
pharmaceutically acceptable carrier.
[0015] It is a further object of the present invention to provide a
method for alleviating a symptom of a cancer, such as colorectal
cancer, hepatocellular carcinoma, bladder cancer, and breast
cancer, including the step of contacting the cancer cell with a
pharmaceutically effective amount of a compound identified by the
method described above.
[0016] These and other objects, features and advantages of the
invention will become more fully apparent when the following
detailed description is read in conjunction with the accompanying
figures and examples, as well as the claims appended hereto.
[0017] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. In
addition, the words "a", "an" and "the" as used herein mean "at
least one" unless otherwise specifically indicated.
[0018] Although methods and materials similar or equivalent to
those described herein can be used in the practice or testing of
the present invention, suitable methods and materials are described
herein below.
[0019] All publications, patent applications, patents, and other
references mentioned herein are incorporated by reference in their
entirety. In case of conflict, the present specification, including
definitions, will control. In addition, the materials, methods, and
examples are illustrative only and not intended to be limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 depicts the MTase activity of SMYD3 on recombinant
RB1 proteins. Part a depicts the results of an in vitro MTase assay
using recombinant histone H3, p53, or C-terminal region of RB1 as
substrate. Equal amount of substrate was incubated with
immunoprecipitated Flag-tagged SMYD3 and .sup.3H-labeled SAM, a
methyl donor. Proteins were separated on SDS-PAGE, and methylated
substrate was detected by fluorogram. Total amount of substrate was
examined by immuno-blot analysis using specific antibody. Part b
depicts the dose-dependent MTase activity of recombinant SMYD3 on
histone H3 and C-terminal RB1 proteins. Part c depicts the MTase
activity of SMYD3 on C-terminal and full-length RB1 (lane 2 and 4,
respectively). Mutant SMYD3 containing a deletion in the conserved
amino acids (SMYD3.DELTA.EEL) markedly decreased the MTase activity
(lane 3).
[0021] FIG. 2 depicts the association between SMYD3 and RB1 in
vivo. Part a depicts the results of an immunoassay. Specifically,
immunoprecipitants from lysates of HepG2 or HCT116 cells using
anti-SMYD3 antibody were immunoblotted with anti-RB1 antibody. Part
b depicts the interaction between wild type and deleted forms of
RB1 (RB1.DELTA.1 and RB1.DELTA.2) and SMYD3 in HEK293 cells
(Lower). Conserved regions and expression constructs of RB1 are
shown in the upper panel. Part c depicts the region of SMYD3
responsible for the interaction with RB1. Conserved regions and
expression constructs of SMYD3 are illustrated in the upper panel.
Part d depicts the in vitro methyltransferase activity of SMYD3 to
histone H3 with/without recombinant RB1. Methylation of histone H3
was unaffected by RB1 (upper panel). Equal amounts of recombinant
human histone H3 protein were used as substrate (lower panel). Part
e depicts the in vitro analysis of histone H4-K20 methylation.
Immunoprecipitated or recombinant SMYD3 protein was incubated with
recombinant human histone H4 as substrate. Immunoprecipitated
Suv4-20h2 protein served as a positive control. Methylated H4-K20
was detected with anti-tri-methyl H4-K20 antibody.
[0022] FIG. 3 depicts the methylation of K824 in the C-terminal
region of RB1. Part a is a schematic representation of the
conserved domains of RB1, and wild type and mutated forms of
C-terminal RB1 protein (K824A, K889A, and K896A). Part b depicts
the detection by autoradiography of methylated C-terminal RB1
separated on SDS-PAGE. Part c depicts MTase activity measured by
liquid scintillation counter. Part d depicts the in vitro
methylation of recombinant wild-type and mutant forms of RB1
proteins, including K791A, K814A, K824A, K791/K824A, and
K814/K824A. RB1 was incubated with recombinant SMYD3 protein in the
presence of .sup.3H-labeled SAM. Methylated RB1 was separated on
SDS-PAGE and detected by fluorogram. Part e depicts methylated RB1
measured by liquid scintillation counter. Part f depicts the di-
and tri-methylation of RB1 lysine 824 by SMYD3. Methylated
wild-type RB1 protein in the presence or absence of SMYD3 was
detected by 3H-BAS imaging system (upper panel). Western-blot
analysis of the RB1 protein using anti-di-methylated lysine 824
(second panel) or anti-tri-methylated lysine 824 (third panel)
antibodies. Total amount of RB1 was quantified with anti-RB1
antibody (fourth panel).
[0023] FIG. 4 depicts the methylation of RB1 by SMYD3 in vivo. Part
a depicts the expression of SMYD3 in HEK-SMYD3 (HEK-SMYD3-1 and -2)
cells and HEK-Mock (HEK-Mock-1 and -2) cells (upper panel). Part b
depicts the detection of methylated RB1 in vivo by radiogram using
immunoprecipitants from HEK-SMYD3 and HEK-Mock cells with anti-RB1
antibody (upper panel). The amount of immunoprecipitated RB1 was
unchanged. Cells were treated with .sup.3H-labeled SAM in the
presence of protein synthesis inhibitor. The amount of
immunoprecipitated RB1 was unchanged (lower panel). Part c depicts
the results of a western blot analyzing the methylation of the
immunoprecipitated RB1 using anti-pan-methyl lysine, anti-di-methyl
lysine 824 and anti-tri-methyl lysine 824 antibodies. Parts d-k
depict the results of immunocytochemical staining of HEK293-SMYD3
cells with anti-di-methyl lysine 824 (d) or anti-tri-methyl lysine
824 (h) antibodies. Parts e and i depict the expression of SMYD3
examined using anti-SMYD3 antibody. Parts f and j depict the
results of nuclear staining with DAPI. Parts g and k constitute
merged images of d-f (g) or h-j (k). Cells abundantly expressing
SMYD3 showed enhanced di- and tri-methylation of RB1 Lys 824 in
vivo.
[0024] FIG. 5 depicts the enhanced phosphorylation of RB1 by SMYD3
Part a depicts the in vitro phosphorylation of C-terminal RB1 by
CDK2/cyclin E in the presence or absence of SMYD3. SMYD3 alone
failed to increase the phosphorylation. Part b depicts the in vitro
phosphorylation of C-terminal RB1 by CDK6/cyclinD3 in the presence
or absence of SMYD3. Enhancement of RB1 phosphorylation by SMYD3
was repressed using K824A substituted RB1. Part c depicts the in
vitro phosphorylation of C-terminal RB1 by CDK2/cyclin E comparing
wild-type (Wt) and K824A mutant (K824A) as a substrate. Part d
depicts the in vitro phosphorylation of C-terminal RB1 by
CDK6/cyclin D3 comparing Wt and K824A as a substrate. Part e
depicts the increased Ser807/811, and Thr821/826 phosphorylation by
CDK2/cyclin E or CDK6/cyclinD3 complexes in the presence of SMYD3.
Part f depicts the elevated Ser807/811 and Thr821/826
phosphorylation in HEK-SMYD3 cells as compared to HEK-Mock cells.
Immunocytochemical staining of HEK293 cells expressing exogenous
SMYD3. Part g depicts the results of staining phosphorylated RB1 in
the cells with anti-phospho RB1 (Thr 821/826) antibody. Part h
depicts the expression of SMYD3 in the cells. Part i depicts the
results of nuclear staining with DAPI. Part j constitutes a merged
image of g-i. Cells expressing SMYD3 showed enhanced
phosphorylation of Thr821/826 in vivo.
[0025] FIG. 6 depicts the methylation and enhanced phosphorylation
of RB1 by SMYD3. In part a, RB1 protein was immunoprecipitated from
SNU475 cells transfected with wild type (p3xFlag-SMYD3) or mutant
SMYD3 plasmids (p3xFlag-SMYD3.DELTA.EEL and
p3xFlag-SMYD3.DELTA.NHSC). Western blot analysis was carried out
with anti-di-methylated lysine 824 (top panel), anti-tri-methylated
lysine 824 (second panel), anti-phospho-serines 807/811 (third
panel), or anti-phospho-threonines 821/824 (fourth panel)
antibodies using the precipitants. Immunoblot analysis with
anti-RB1 antibody served for a quantity control (bottom panel).
Part b depicts the di- and tri-methylation of lysine 824, and
phosphorylation of Ser807/811 and Thr821/826 in two breast cancer
tissues. Western blot analysis was carried out with
anti-di-methylated lysine 824, anti-tri-methylated lysine 824,
anti-phospho RB (Ser807/811), or anti-phospho RB (Thr821/824)
antibodies.
[0026] FIG. 7 depicts the augmented E2F-transcriptional activity in
HEK-SMYD3 cells. Luciferase activity was measured 24 h after
transfection with E2F-luciferase vector in HEK-SMYD3 and HEK-Mock
cells. Immunocytochemical staining of HEK293 cells expressing
exogenous SMYD3. Phosphorylated RB1 in the cells was stained with
anti-phospho RB1 (Thr 821/826) antibody. Part h depicts the
expression of SMYD3 in the cells. Part i depicts the results of
nuclear staining with DAPI. Part j constitutes a merged image of
a-c. Cells expressing SMYD3 showed enhanced phosphorylation of
Thr821/826 in vivo.
[0027] FIG. 8 Expression patter of SMYD3 protein. Part a depicts
Expression of SMYD3 protein in human cancer cell lines and tissues.
Western blot analysis was carried out using anti-SMYD3 antibody.
Expression of .beta.-actin served as a quantitative control. Part b
depicts immunoblot analysis of HA-tagged SMYD3 (left panel) and
FLAG-tagged (right panel). Western blot analysis was carried out
with anti-HA antibody or anti-FLAG antibody using extracts from
cells expressing HA-tagged SMYD3 in the N-terminal region or
Flag-tagged SMYD3 in the C-terminal region, respectively. Part c
depicts schematic presentation of deleted forms of SMYD3. Plasmids
expressing a series of FLAG-tagged SMYD3 in its N-terminal region
were transfected into HEK293 cells that do not express endogenous
SMYD3. Part d depicts western blot analysis of extracts from the
cells was performed using anti-SMYD3 antibody (upper panel) or
anti-FLAG antibody (lower panel). Arrows indicate full-length SMYD3
protein, and an asterisk corresponds to a cleaved form of
SMYD3.
[0028] FIG. 9 Determination of SMYD3 cleavage site and conserved
amino acid sequences of SET-N region in SET containing protein.
Part a depicts Edman amino acid sequence determined a 34
amino-acid-deleted SMYD3 protein in its N-terminal region. Part b
depicts alignment of amino acid sequences of SET-N in histone
methyltransferases. Highly conserved amino acids were indicated in
black boxes and moderately conserved amino acids were in shadowed
boxes.
[0029] FIG. 10 Increased HMTase activity of the cleaved form of
SMYD3 compared with the wild type protein. Part a depicts western
blot analysis of wild-type or deleted forms (.DELTA.N34 and
.DELTA.N44) of SMYD3 proteins with anti-FLAG antibody (upper panel)
and anti-SMYD3 antibody (middle panel). Proteins were extracted
from cells expressing FLAG-tagged SMYD3 proteins.
Immunoprecipitated SMYD3 protein was used for an HMTase assay. Part
b depicts dose-response increase of HMTase activity of the
full-length and cleaved SMYD3 proteins. Addition of SAHH
(S-adenosyl homocysteine hydrolase) increased the activity.
3H-radioactivity was measured by liquid scintillation counter.
[0030] FIG. 11 Determination of responsible region for the
suppressed HMTase activity in the SET-N region. Part a depicts
schematic presentation of mutated SMYD3 constructs containing
substitution in the conserved amino acids of the SET-N region. Part
b depicts immunoblot analysis of FLAG-tagged wild-type or mutant
(.DELTA.N34, SETNm1, SETNm2, and SETNm3) SMYD3 proteins with
anti-SMYD3 (upper panel) or anti-FLAG (middle panel) antibody.
Immunoprecipitated protein with anti-Flag antibody from HEK293F
cells expressing FLAG-tagged SMYD3 was used as enzyme source for
HMTase assay. Part c depicts HMTase activity of the wild-type,
deleted forms of SMYD3. 3H-radioactivity was measured by liquid
scintillation counter.
[0031] FIG. 12 Enhanced HMTase activity by the deletion of
N-terminal region in SMYD3. Part a depicts Schematic presentation
of deleted forms of SMYD3 in its N-terminal region. Plasmids
expressing a series of GST-fused SMYD3 proteins were prepared. Part
b depicts immunoblot analysis of recombinant SMYD3 proteins with
anti-GST antibody. Wild-type and mutant recombinant SMYD3 proteins
fused with GST were expressed in bacterial cells, and purified from
the cells. Part c depicts in vitro HMTase activity of the proteins.
3H-radioactivity was measured by liquid scintillation counter.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The SMYD3 cDNA consists of 1622 nucleotides that contain an
open reading frame of 1284 nucleotides as set forth in SEQ. ID.
NO.:1. The open reading frame encodes a 428-amino acid protein with
a zinc finger motif and a SET domain, as shown in SEQ. ID. NO.:2.
The zinc finger domain (MYND) extends from amino acid 49 to amino
acid 87 and the SET (Su 3-9, Enhancer-of-zeste, Trihorrax) domain
extends from amino acid 117 to amino acid 246.
[0033] The subcellular localization of the SMYD3 protein is altered
during cell cycle progression and by the density of cultured cells.
The SMYD3 protein accumulates in the nucleus when cells are in
middle to late S phase or cultured in sparse conditions. However,
the SMYD3 protein localizes in the cytoplasm as well as in the
nucleus when cells are in other phases of the cell cycle or grown
in a dense condition.
[0034] The present invention thus provides a method of screening
for an agent that modulates SMYD3 methyltransferase activity. The
method is practiced by contacting an SMYD3 polypeptide or a
functional equivalent thereof having methyltransferase activity
with a retinoblastoma protein, and assaying methyltransferase
activity of the contacted SMYD3 or its functional equivalent. An
agent that modulates methyltransferase activity of the SMYD3 or
functional equivalent is thereby identified.
[0035] In the present invention, the term "functionally equivalent"
means that the subject protein or polypeptide has the same or
substantially the same methyltransferase activity as SMYD3. In
particular, the protein catalyzes the methylation of a
retinoblastoma protein or a fragment of a retinoblastoma protein
that includes lysine 824. Whether a subject protein has the target
activity can be routinely determined by the present invention.
Namely, the methyltransferase activity can be determined by (a)
contacting a polypeptide with a substrate (e.g., a retinoblastoma
protein or a fragment that includes lysine 824) and a co-factor
(e.g., S-adenosyl-L-methionine) under conditions suitable for
methylation of the substrate, and (b) detecting the methylation
level of the substrate.
[0036] As used herein, the term "retinoblastoma peptide" refers to
full length retinoblastoma proteins (e.g., SEQ ID NO: 4) as well as
mutants and fragments thereof. Examples of functional fragments
include, but are not limited to, C-terminal fragment such as the
fragment composed of amino acids 769 to 921 of SEQ ID NO: 4.
Preferred fragments include the lysine residue at position 824.
Examples of functional mutants include, but are not limited to, the
following RB1 mutants that retain the methylation capacity of the
full length retinoblastoma protein: K889A, K896A, K791A, K814A,
K791A/K824A, and K814A/K824A.
[0037] Methods for preparing proteins that are functional
equivalents of a given protein are well known to those skilled in
the art and include conventional methods of introducing mutations
into the protein. For example, one skilled in the art can prepare
proteins functionally equivalent to the human SMYD3 protein by
introducing an appropriate mutation in the amino acid sequence of
the human SMYD3 protein using site-directed mutagenesis for example
(Hashimoto-Gotoh, T. et al. (1995), Gene 152, 271-275; Zoller, M J,
and Smith, M. (1983), Methods Enzymol. 100, 468-500; Kramer, W. et
al. (1984), Nucleic Acids Res. 12, 9441-9456; Kramer W, and Fritz H
J. (1987) Methods. Enzymol. 154, 350-367; Kunkel, T A (1985), Proc.
Natl. Acad. Sci. USA. 82, 488-492). Amino acid mutations can occur
in nature, too. A SMYD3 polypeptide useful in the context of the
present invention includes those proteins having the amino acid
sequences of the human SMYD3 protein in which one or more amino
acids are mutated, provided the resulting mutated proteins are
functional equivalents of the human SMYD3 protein, more
particularly retain the methyltransferase activity of the human
SMYD3 protein. The number of amino acids to be mutated in such a
mutant is generally 20 amino acids or less, typically 10 amino
acids or less, preferably 6 amino acids or less, and more
preferably 3 amino acids or less. To maintain the methyltransferase
activity, the SET-domain "NHSCXXN" and "GEELXXXY" are preferably
conserved in the amino acid sequence of the mutated proteins ("X"
indicates any amino acid).
[0038] Mutated or modified proteins, i.e., proteins having amino
acid sequences modified by deleting, adding and/or replacing one or
more amino acid residues of a certain amino acid sequence, are
known to retain the biological activity of the original protein
(Mark, D. F. et al., Proc. Natl. Acad. Sci. USA (1984) 81,
5662-5666, Zoller, M. J. & Smith, M., Nucleic Acids Research
(1982) 10, 6487-6500, Wang, A. et al., Science 224, 1431-1433,
Dalbadie-McFarland, G. et al., Proc. Natl. Acad. Sci. USA (1982)
79, 6409-6413).
[0039] The amino acid residue to be mutated is preferably mutated
into a different amino acid that allows the properties of the amino
acid side-chain to be conserved (a process known as conservative
amino acid substitution). Examples of properties of amino acid side
chains include hydrophobic amino acids (A, I, L, M, F, P, W, Y, V),
hydrophilic amino acids (R, D, N, C, E, Q, G, H, K, S, T), and side
chains having the following functional groups or characteristics in
common: an aliphatic side-chain (G, A, V, L, I, P); a hydroxyl
group containing side-chain (S, T, Y); a sulfur atom containing
side-chain (C, M); a carboxylic acid and amide containing
side-chain (D, N, E, Q); a base containing side-chain (R, K, H);
and an aromatic containing side-chain (H, F, Y, W). Note, the
parenthetic letters indicate the one-letter codes of amino
acids.
[0040] An example of a protein in one or more amino acids residues
are added to the amino acid sequence of human SMYD3 protein (SEQ ID
NO: 2) is a fusion protein containing the human SMYD3 protein.
Fusion proteins include fusions of the human SMYD3 protein and
other peptides or proteins, and are used in the present invention.
Fusion proteins can be made by techniques well known to a person
skilled in the art, such as by linking the DNA encoding the human
SMYD3 protein of the invention with DNA encoding other peptides or
proteins, so that the frames match, inserting the fusion DNA into
an expression vector and expressing it in a host. There is no
restriction as to the peptides or proteins fused to the protein of
the present invention.
[0041] Known peptides that can be used as peptides to be fused to
the SMYD3 protein include, for example, FLAG (Hopp, T. P. et al.,
Biotechnology (1988) 6, 1204-1210), 6.times.His containing six His
(histidine) residues, 10.times.His, Influenza agglutinin (HA),
human c-myc fragment, VSP-GP fragment, p18HIV fragment, T7-tag,
HSV-tag, E-tag, SV40T antigen fragment, lck tag, .alpha.-tubulin
fragment, B-tag, Protein C fragment, and the like. Examples of
proteins that may be fused to a protein of the invention include
GST (glutathione-S-transferase), Influenza agglutinin (HA),
immunoglobulin constant region, .beta.-galactosidase, MBP
(maltose-binding protein), and such.
[0042] Fusion proteins can be prepared by fusing commercially
available DNA, encoding the fusion peptides or proteins discussed
above, with the DNA encoding the protein of the present invention
and expressing the fused DNA prepared.
[0043] An alternative method known in the art to isolate
functionally equivalent proteins uses hybridization techniques to
identify homologous sequences (Sambrook, J. et al., Molecular
Cloning 2nd ed. 9.47-9.58, Cold Spring Harbor Lab. Press, 1989).
One skilled in the art can readily isolate a DNA having high
homology with a whole or part of the SMYD3 DNA sequence (e.g., SEQ
ID NO: 1) encoding the human SMYD3 protein, and isolate proteins
that are functionally equivalent to the human SMYD3 protein from
the isolated DNA. The proteins used for the present invention
include those that are encoded by DNA that hybridize with a whole
or part of the DNA sequence encoding the human SMYD3 protein and
are functional equivalents of the human SMYD3 protein. These
proteins include mammal homologues corresponding to the protein
derived from human or mouse (for example, a protein encoded by a
monkey, rat, rabbit and bovine gene). In isolating a cDNA highly
homologous to the DNA encoding the human SMYD3 protein from
animals, it is particularly preferable to use tissues from skeletal
muscle, testis, HCC, or colorectal tumors.
[0044] The condition of hybridization for isolating a DNA encoding
a functional equivalent of the human SMYD3 protein can be routinely
selected by a person skilled in the art. For example, hybridization
may be performed by conducting prehybridization at 68.degree. C.
for 30 min or longer using "Rapid-hyb buffer" (Amersham LIFE
SCIENCE), adding a labeled probe, and warming at 68.degree. C. for
1 hour or longer. The following washing step can be conducted, for
example, in a low stringent condition. A low stringency condition
is, for example, 42.degree. C., 2.times. SSC, 0.1% SDS, or
preferably 50.degree. C., 2.times.SSC, 0.1% SDS. More preferably,
highly stringent conditions are used. In the context of the present
invention, a highly stringent condition includes, for example,
washing 3 times in 2.times.SSC, 0.01% SDS at room temperature for
20 min, then washing 3 times in 1.times.SSC, 0.1% SDS at 37.degree.
C. for 20 min, and washing twice in 1.times.SSC, 0.1% SDS at
50.degree. C. for 20 min. However, several factors such as
temperature and salt concentration can influence the stringency of
hybridization and one skilled in the art can suitably select the
factors to achieve the requisite stringency.
[0045] In place of hybridization, a gene amplification method, for
example, the polymerase chain reaction (PCR) method, can be
utilized to isolate a DNA encoding a protein that is functionally
equivalent to the human SMYD3 protein, using a primer synthesized
based on the sequence information of the DNA (SEQ ID NO: 1)
encoding the human SMYD3 protein (SEQ ID NO: 2).
[0046] Proteins that are functional equivalents of the human SMYD3
protein, encoded by DNA isolated through the above hybridization
techniques or by gene amplification techniques, normally have a
high homology to the amino acid sequence of the human SMYD3
protein. "High homology" (also referred to as "high identity")
typically refers to the degree of identity between two optimally
aligned sequences (either polypeptide or polynucleotide sequences).
Typically, high homology or identity refers to homology of 40% or
higher, preferably 60% or higher, more preferably 80% or higher,
even more preferably 85%, 90%, 95%, 98%, 99%, or higher. The degree
of homology or identity between two polypeptide or polynucleotide
sequences can be determined by following the algorithm in "Wilbur,
W. J. and Lipman, D. J. Proc. Natl. Acad. Sci. USA (1983) 80,
726-730".
[0047] A protein useful in the context of the present invention may
have variations in amino acid sequence, molecular weight,
isoelectric point, the presence or absence of sugar chains, or
form, depending on the cell or host used to produce it or the
purification method utilized. Nevertheless, so long as it is a
function equivalent of human SMYD3 protein (SEQ ID NO: 2), it is
useful in the present invention.
[0048] The proteins useful in the context of the present invention
can be prepared as recombinant proteins or natural proteins, by
methods well known to those skilled in the art. A recombinant
protein can be prepared by inserting a DNA encoding a protein of
the present invention (for example, the DNA comprising the
nucleotide sequence of SEQ ID NO: 1), into an appropriate
expression vector, introducing the vector into an appropriate host
cell, obtaining the extract, and purifying the protein by
subjecting the extract to chromatography, for example, ion exchange
chromatography, reverse phase chromatography, gel filtration, or
affinity chromatography utilizing a column to which antibodies
against the protein of the present invention is fixed, or by
combining more than one of aforementioned columns.
[0049] In addition, when a protein useful in the context of the
present invention is expressed within host cells (for example,
animal cells and E. coli) as a fusion protein with
glutathione-S-transferase protein or as a recombinant protein
supplemented with multiple histidines, the expressed recombinant
protein can be purified using a glutathione column or nickel
column.
[0050] After purifying the fusion protein, it is also possible to
exclude regions other than the objective protein by cutting with
thrombin or factor-Xa as required.
[0051] A natural protein can be isolated by methods known to a
person skilled in the art, for example, by contacting an affinity
column, in which antibodies binding to the SMYD3 protein described
below are bound, with the extract of tissues or cells expressing
the protein of the present invention. The antibodies can be
polyclonal antibodies or monoclonal antibodies.
[0052] In the present invention, the methyltransferase activity of
a SMYD3 polypeptide can be determined by methods known in the art.
For example, a SMYD3 polypeptide and a retinoblastoma peptide
substrate can be incubated with a labeled methyl donor, under
suitable assay conditions. Examples of preferred methyl donors
include, but are not limited to,
S-adenosyl-[methyl-.sup.14C]-L-methionine, and
S-adenosyl-[methyl-.sup.3H]-L-methionine preferably. Transfer of
the radiolabel to the retinoblastoma peptide can be detected, for
example, by SDS-PAGE electrophoresis and fluorography.
Alternatively, following the reaction, the retinoblastoma peptides
can be separated from the methyl donor by filtration, and the
amount of radiolabel retained on the filter quantitated by
scintillation counting. Other suitable labels that can be attached
to methyl donors, such as chromogenic and fluorescent labels, and
methods of detecting transfer of these labels to retinoblastoma
peptides, are known in the art.
[0053] Alternatively, the methyltransferase activity of SMYD3 can
be determined using an unlabeled methyl donor (e.g.
S-adenosyl-L-methionine) and reagents that selectively recognize
methylated retinoblastoma peptides. For example, after incubation
of SMYD3, substrate to be methylated and methyl donor, under
conditions suitable for methylation of the substrate, methylated
substrate can be detected using conventional immunological methods.
Any immunological techniques that uses an antibody to recognize a
methylated substrate can be used for the detection.
[0054] Furthermore, it was confirmed that phosphorylation of RB1 at
Ser 807 and Ser 811 was enhanced in the methlated RB1 at Lys 824.
Accordingly, in another embodiments, methylation level of the RB1
may be estimated via phosphorylation of RB1. Kinase such as CDK2 or
CDK6 may also be required for the phosphorylation of RB1. The
phosphorylation of RB1 may be detected using radiolabeled phosphate
donor. Alternatively, antibody recognising phosphorylation site of
RB1 may be used for estimating phosphorylation level of RB1.
[0055] Various low-throughput and high-throughput enzyme assay
formats are known in the art and can be readily adapted for
detection or measuring of the methyltransferase activity of SMYD3.
For high-throughput assays, the retinoblastoma peptide substrate
can conveniently be immobilized on a solid support, such as a
multiwell plate, slide or chip. Following the reaction, the
methylated product can be detected on the solid support by the
methods described above. Alternatively, the methyltransferase
reaction can take place in solution, after which the retinoblastoma
peptide can be immobilized on a solid support, and the methylated
product detected. To facilitate such assays, the solid support can
be coated with streptavidin and the retinoblastoma labeled with
biotin, or the solid support can be coated with anti-retinoblastoma
antibodies. The skilled person can determine suitable assay formats
depending on the desired throughput capacity of the screen.
[0056] The present invention also encompasses the use of partial
peptides of a protein of the present invention. A partial peptide
has an amino acid sequence specific to the SMYD3 protein and
consists of less than about 400 amino acids, usually less than
about 200 and often less than about 100 amino acids, and at least
about 7 amino acids, preferably about 8 amino acids or more, and
more preferably about 9 amino acids or more. The partial peptide
can be used, for example, in the screening for an agent or compound
that binds to the SMYD3 protein, and the screening for inhibitors
of the binding between SMYD3 and a co-factor thereof, such as, for
example, SAM. The partial peptide containing the SET-domain is
preferably used for such screening.
[0057] A partial peptide useful in the context of the present
invention can be produced by genetic engineering, by known methods
of peptide synthesis, or by digesting the protein of the invention
with an appropriate peptidase. For peptide synthesis, for example,
solid phase synthesis or liquid phase synthesis may be used.
[0058] A SMYD3 mutant having a mutation of SET-domain shows
inhibitory effects on cell proliferation. Therefore, a partial
peptide of SMYD3 preferably includes the SET-domain "NHSCXXN"
and/or "GEELXXXY".
[0059] Any test agent can be used. Examples include, but are not
limited to, cell extracts, cell culture supernatant, products of
fermenting microorganism, extracts from marine organism, plant
extracts, purified or crude proteins, peptides, non-peptide
compounds, synthetic micromolecular compounds and natural
compounds.
[0060] Test agents or compounds useful in the assays described
herein can also take the form of antibodies that specifically bind
to SMYD3 or partial SMYD3 peptides that lack methyltransferase
activity. For example, antibodies (e.g., monoclonal antibodies) can
be tested for the ability to block the binding between SMYD3 and
its retinoblastoma substrate.
[0061] An agent or compound isolated by the screening methods of
the present invention is a candidate for drugs that inhibit the
methyltransferase activity of SMYD3 and, thus, can be applied to
the treatment or prevention of hepatocellular, colorectal, breast
and/or bladder cancer.
[0062] Moreover, agents or compounds in which a part of the
structure of the agent or compound inhibiting the methyltransferase
activity of SMYD3 is converted by addition, deletion and/or
replacement are also included in the agents and compounds
obtainable by the screening methods of the present invention.
[0063] As noted above, the agents or compounds that inhibit the
methyltransferase activity of SMYD3 can be either partial peptides
that lack the methyltransferase activity of SMYD3 or can be
antibodies against SMYD3. As used herein, the term "antibody"
refers to an immunoglobulin molecule having a specific structure,
that interacts (i.e., binds) only with the antigen that was used
for synthesizing the antibody or with an antigen closely related
thereto. Furthermore, an antibody may be a fragment of an antibody
or a modified antibody, so long as it binds to the proteins encoded
by SMYD3 gene. For instance, the antibody fragment may be Fab,
F(ab').sub.2, Fv, or single chain Fv (scFv), in which Fv fragments
from H and L chains are ligated by an appropriate linker (Huston J.
S. et al. Proc. Natl. Acad. Sci. U.S.A. 85:5879-5883 (1988)). More
specifically, an antibody fragment may be generated by treating an
antibody with an enzyme, such as papain or pepsin. Alternatively, a
gene encoding the antibody fragment may be constructed, inserted
into an expression vector, and expressed in an appropriate host
cell (see, for example, Co M. S. et al. J. Immunol. 152:2968-2976
(1994); Better M. and Horwitz A. H. Methods Enzymol. 178:476-496
(1989); Pluckthun A. and Skerra A. Methods Enzymol. 178:497-515
(1989); Lamoyi E. Methods Enzymol. 121:652-663 (1986); Rousseaux J.
et al. Methods Enzymol. 121:663-669 (1986); Bird R. E. and Walker
B. W. Trends Biotechnol. 9:132-137 (1991)).
[0064] An antibody may be modified by conjugation with a variety of
molecules, such as polyethylene glycol (PEG). The present invention
provides such modified antibodies. The modified antibody can be
obtained by chemically modifying an antibody. Such modification
methods are conventional in the field. Alternatively, an antibody
may comprise as a chimeric antibody having a variable region
derived from a nonhuman antibody and a constant region derived from
a human antibody, or a humanized antibody, comprising a
complementarity determining region (CDR) derived from a nonhuman
antibody, the frame work region (FR) derived from a human antibody
and the constant region. Such antibodies can be prepared by using
known technologies. Humanization can be performed by substituting
rodent CDRs or CDR sequences for the corresponding sequences of a
human antibody (see e.g., Verhoeyen et al., Science 239:1534-1536
(1988)). Accordingly, such humanized antibodies are chimeric
antibodies, wherein substantially less than an intact human
variable domain has been substituted by the corresponding sequence
from a non-human species.
[0065] Fully human antibodies, comprising human variable regions in
addition to human framework and constant regions, can also be used.
Such antibodies can be produced using various techniques that are
known in the art. For example, in vitro methods involving the use
of recombinant libraries of human antibody fragments displayed on
bacteriophage may be used (e.g., Hoogenboom & Winter, J. Mol.
Biol. 227:381 (1991)), Similarly, human antibodies can be made by
introducing of human immunoglobulin loci into transgenic animals,
e.g., mice in which the endogenous immunoglobulin genes have been
partially or completely inactivated. This approach is described,
e.g., in U.S. Pat. Nos. 6,150,584, 5,545,807; 5,545,806; 5,569,825;
5,625,126; 5,633,425; 5,661,016.
[0066] When administrating an agent or compound isolated by a
method of the present invention as a pharmaceutical for humans and
other mammals, such as mice, rats, guinea-pigs, rabbits, cats,
dogs, sheep, pigs, cattle, monkeys, baboons, and chimpanzees, the
isolated agent or compound can be directly administered or can be
formulated into a dosage form using known pharmaceutical
preparation methods. For example, according to the need, the drugs
can be taken orally, as sugar-coated tablets, capsules, elixirs and
microcapsules, or non-orally, in the form of injections of sterile
solutions or suspensions with water or any other pharmaceutically
acceptable liquid. For example, the agents or compounds can be
mixed with pharmaceutically acceptable carriers or media,
specifically, sterilized water, physiological saline, plant-oils,
emulsifiers, suspending agents, surfactants, stabilizers, flavoring
agents, excipients, vehicles, preservatives, binders, and such in a
unit dose form required for generally accepted drug implementation.
The amount of active ingredients in these preparations makes a
suitable dosage within the indicated range acquirable.
[0067] Examples of additives that can be mixed to tablets and
capsules are, binders such as gelatin, corn starch, tragacanth gum
and arabic gum; excipients such as crystalline cellulose; swelling
agents such as corn starch, gelatin and alginic acid; lubricants
such as magnesium stearate; sweeteners such as sucrose, lactose or
saccharin; and flavoring agents such as peppermint, Gaultheria
adenothrix oil and cherry. When the unit-dose form is a capsule, a
liquid carrier, such as an oil, can also be further included in the
above ingredients. Sterile composites for injections can be
formulated following normal drug implementations using vehicles
such as distilled water used for injections.
[0068] Physiological saline, glucose, and other isotonic liquids
including adjuvants, such as D-sorbitol, D-mannose, D-mannitol, and
sodium chloride, can be used as aqueous solutions for injections.
These can be used in conjunction with suitable solubilizers, such
as alcohol, specifically ethanol, polyalcohols such as propylene
glycol and polyethylene glycol, non-ionic surfactants, such as
Polysorbate 80 .TM. and HCO-50.
[0069] Sesame oil or soy-bean oil can be used as a oleaginous
liquid and may be used in conjunction with benzyl benzoate or
benzyl alcohol as a solubilizer and may be formulated with a
buffer, such as phosphate buffer and sodium acetate buffer; a
pain-killer, such as procaine hydrochloride; a stabilizer, such as
benzyl alcohol and phenol; and an anti-oxidant. The prepared
injection may be filled into a suitable ampule.
[0070] Methods well known to one skilled in the art may be used to
administer a pharmaceutical composition of the present invention to
patients, for example as intraarterial, intravenous, or
percutaneous injections and also as intranasal, intramuscular or
oral administrations. The dosage and method of administration vary
according to the body-weight and age of a patient and the
administration method; however, one skilled in the art can
routinely select a suitable method of administration. In addition,
if the agent or compound of interest is encodable by a DNA, the DNA
can be inserted into a vector for gene therapy and the vector
administered to a patient to perform the therapy. The dosage and
method of administration vary according to the body-weight, age,
and symptoms of the patient but one skilled in the art can suitably
select them.
[0071] For example, although the dose of an agent or compound that
binds to SMYD3 and regulates its activity depends on the symptoms,
a typical dose ranges from about 0.1 mg to about 100 mg per day,
preferably about 1.0 mg to about 50 mg per day and more preferably
about 1.0 mg to about 20 mg per day, when administered orally to a
normal adult (weight 60 kg).
[0072] When administering parenterally, in the form of an injection
to a normal adult (weight 60 kg), although there are some
differences according to the patient, target organ, symptoms and
method of administration, it is convenient to intravenously inject
a dose of about 0.01 mg to about 30 mg per day, preferably about
0.1 to about 20 mg per day and more preferably about 0.1 to about
10 mg per day. Also, in the case of other animals too, it is
possible to administer an amount converted to 60 kgs of
body-weight.
[0073] The present invention further provides a method for treating
cancer in a subject, such as hepatocellular carcinoma, colorectal
carcinoma, bladder cancer and breast cancer. Administration can be
prophylactic or therapeutic to a subject at risk of (or susceptible
to) a disorder or having a disorder associated with aberrant the
methyltransferase activity of SMYD3. The method includes decreasing
the function of SMYD3 in a suitable cancer cell. Function can be
inhibited through the administration of an agent or compound
obtained by a screening method of the present invention.
[0074] In another aspect, the present invention includes
pharmaceutical, or therapeutic, compositions containing one or more
therapeutic agents or, compounds described herein. Alternatively,
the present invention also provides use of one or more therapeutic
agents or compounds described herein for manufacturing a
pharmaceutical, or therapeutic, compositions for treating and/or
preventing of cancer, more particularly hepatocellular carcinoma,
colorectal carcinoma, bladder cancer and breast cancer.
Pharmaceutical formulations may include those suitable for oral,
rectal, nasal, topical (including buccal and sub-lingual), vaginal
or parenteral (including intramuscular, sub-cutaneous and
intravenous) administration, or for administration by inhalation or
insufflation. The formulations may, where appropriate, be
conveniently presented in discrete dosage units and may be prepared
by any of the methods well known in the art of pharmacy. All such
pharmacy methods include the steps of bringing into association the
active compound with liquid carriers or finely divided solid
carriers or both as needed and then, if necessary, shaping the
product into the desired formulation.
[0075] Pharmaceutical formulations suitable for oral administration
may conveniently be presented as discrete units, such as capsules,
cachets or tablets, each containing a predetermined amount of the
active ingredient; as a powder or granules; or as a solution, a
suspension or as an emulsion. The active ingredient may also be
presented as a bolus electuary or paste, and be in a pure form,
i.e., without a carrier. Tablets and capsules for oral
administration may contain conventional excipients such as binding
agents, fillers, lubricants, disintegrant or wetting agents. A
tablet may be made by compression or molding, optionally with one
or more formulational ingredients. Compressed tablets may be
prepared by compressing in a suitable machine the active
ingredients in a free-flowing form such as a powder or granules,
optionally mixed with a binder, lubricant, inert diluent,
lubricating, surface active or dispersing agent. Molded tablets may
be made by molding in a suitable machine a mixture of the powdered
compound moistened with an inert liquid diluent. The tablets may be
coated according to methods well known in the art. Oral fluid
preparations may be in the form of, for example, aqueous or oily
suspensions, solutions, emulsions, syrups or elixirs, or may be
presented as a dry product for constitution with water or other
suitable vehicle before use. Such liquid preparations may contain
conventional additives such as suspending agents, emulsifying
agents, non-aqueous vehicles (which may include edible oils), or
preservatives. The tablets may optionally be formulated so as to
provide slow or controlled release of the active ingredient
therein.
[0076] Formulations for parenteral administration include aqueous
and non-aqueous sterile injection solutions which may contain
anti-oxidants, buffers, bacteriostats and solutes which render the
formulation isotonic with the blood of the intended recipient; and
aqueous and non-aqueous sterile suspensions which may include
suspending agents and thickening agents. The formulations may be
presented in unit dose or multi-dose containers, for example sealed
ampoules and vials, and may be stored in a freeze-dried
(lyophilized) condition requiring only the addition of the sterile
liquid carrier, for example, saline, water-for-injection,
immediately prior to use. Alternatively, the formulations may be
presented for continuous infusion. Extemporaneous injection
solutions and suspensions may be prepared from sterile powders,
granules and tablets of the kind previously described.
[0077] Formulations for rectal administration may be presented as a
suppository with the usual carriers such as cocoa butter or
polyethylene glycol. Formulations for topical administration in the
mouth, for example buccally or sublingually, include lozenges,
comprising the active ingredient in a flavored base such as sucrose
and acacia or tragacanth, and pastilles comprising the active
ingredient in a base such as gelatin and glycerin or sucrose and
acacia. For intra-nasal administration the compounds obtained by
the invention may be used as a liquid spray or dispersible powder
or in the form of drops. Drops may be formulated with an aqueous or
non-aqueous base also comprising one or more dispersing agents,
solubilizing agents or suspending agents. Liquid sprays are
conveniently delivered from pressurized packs.
[0078] For administration by inhalation the compounds are
conveniently delivered from an insufflator, nebulizer, pressurized
packs or other convenient means of delivering an aerosol spray.
Pressurized packs may comprise a suitable propellant such as
dichlorodifluoromethane, trichlorofluoromethane,
dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In
the case of a pressurized aerosol, the dosage unit may be
determined by providing a valve to deliver a metered amount.
[0079] Alternatively, for administration by inhalation or
insufflation, the compounds may take the form of a dry powder
composition, for example a powder mix of the compound and a
suitable powder base such as lactose or starch. The powder
composition may be presented in unit dosage form, in for example,
capsules, cartridges, gelatin or blister packs from which the
powder may be administered with the aid of an inhalator or
insufflators.
[0080] When desired, the above described formulations, adapted to
give sustained release of the active ingredient, may be employed.
The pharmaceutical compositions may also contain other active
ingredients such as antimicrobial agents, immunosuppressants or
preservatives.
[0081] It should be understood that in addition to the ingredients
particularly mentioned above, the formulations of this invention
may include other agents conventional in the art having regard to
the type of formulation in question, for example, those suitable
for oral administration may include flavoring agents.
[0082] Preferred unit dosage formulations are those containing an
effective dose, as recited below, or an appropriate fraction
thereof, of the active ingredient.
[0083] For each of the aforementioned conditions, the compositions
may be administered orally or via injection at a dose of from about
0.1 to about 250 mg/kg per day. The dose range for adult humans is
generally from about 5 mg to about 17.5 g/day, preferably about 5
mg to about 10 g/day, and most preferably about 100 mg to about 3
g/day. Tablets or other unit dosage forms of presentation provided
in discrete units may conveniently contain an amount which is
effective at such dosage or as a multiple of the same, for
instance, units containing about 5 mg to about 500 mg, usually from
about 100 mg to about 500 mg.
[0084] The pharmaceutical composition preferably is administered
orally or by injection (intravenous or subcutaneous), and the
precise amount administered to a subject will be the responsibility
of the attendant physician. However, the dose employed will depend
upon a number of factors, including the age and sex of the subject,
the precise disorder being treated, and its severity. Also the
route of administration may vary depending upon the condition and
its severity.
[0085] The following examples are merely illustrative and are not
intended to limit the scope of the present invention. While aspects
of the present invention are described in the following examples,
those skilled in the art will recognize that other methods and
materials similar or equivalent to those described herein can be
used in the practice or testing of the present invention.
EXAMPLES
Materials and Methods
Reagents:
[0086] Anti-RB (IF8), anti-phospho RB (Ser 807/811, sc-16670), and
anti-phospho RB (Thr 821/826) antibodies were purchased from Santa
Cruz Biotechnology, anti-Flag antibody from SIGMA, and
anti-pan-methyl lysine antibody (ab7315) was from Abeam Ltd.
Recombinant SMYD3 protein or synthetic RB1 peptides (residues
820-828) containing di- or tri-methylated lysine 824 were
inoculated into rabbits (SIGMA-ALDRICH, St. Louis, Mo.), and
polyclonal antibodies were purified from sera of the immunized
rabbits. Recombinant C-terminal GST-RB1 and full-length GST-p53
proteins were from Santa Cruz Biotechnology, His-conjugated
C-terminal RB1, CDK2/cyclin E and CDK6/cyclinD3 proteins were from
Upstate Biotechnology, full-length recombinant RB protein (3108)
was from QED Bioscience. S-(5'-Adenosyl)-L-homocysteine hydrolase
(SAHH) was obtained from SIGMA.
In Vitro Methyltransferase and Kinase Assays:
[0087] 293T cells were transfected with plasmid expressing
Flag-tagged wild-type SMYD3 (p3XFLAG-CMV-SMYD3), mutant SMYD3
(p3XFLAG-CMV-SMYD3.DELTA.EEL), and purified tagged-SMYD3 protein by
immunoprecipitation with anti-Flag antibody. Recombinant SMYD3
protein was prepared in Sf9 cells using Baculovirus system
(Clontech). In vitro HMTase assay was performed with a slight
modification as described elsewhere (Strahl, B. D., et al. Proc
Natl Acad Sci USA 96, 14967-72 (1999)). Briefly, immunoprecipitated
or recombinant SMYD3 protein was mixed with 1 .mu.g of recombinant
histone H3, RB1, or p53 protein in the presence of 2 .mu.Ci of
[methyl-.sup.3H]-labeled S-adenosyl-L-methionine (SAM, Amersham
Biosciences) as methyl donor in methyltransferase buffer (50 mM
Tris-HCl pH 8.5, 100 mM NaCl, 10 mM DTT). The reaction mixture was
incubated for 1 hr at 30.degree. C. Proteins were separated in
SDS-PAGE, and labeled proteins were detected by fluorography. In
vitro kinase assays of CDK2/cyclinE and CDK6/cyclinD3 were carried
out according to the manufacture's protocol (Upstate
Biotechnology). Both non-methylated and methylated RB1 (#12-439,
Upstate Biotechnology) were used as the reaction substrate.
In Vivo Methylation Assay:
[0088] To measure methylated RB1 in vivo, in vivo labeling of RB1
was carried out with [methyl-.sup.3H]-labeled
S-adenosyl-L-methionine in cultured cells, according to the method
described by Liu and Dreyfuss (Liu, Q. & Dreyfuss, G. Mol Cell
Biol 15, 2800-8 (1995)) with slight modification. HEK293 cells were
incubated with 100 .mu.g/ml of cycloheximide and 40 .mu.g/ml of
chloramphenicol at 37.degree. C. for 30 min, when the medium was
then replaced by medium containing 10 .mu.Ci/ml of
L-[methyl-.sup.3H] methionine and the protein synthesis inhibitors
without unlabeled methionine, and maintained for an additional 3 h.
The whole cell lysates were subjected to immunoprecipitation with
anti-RB antibody (IF8; Santa Cruz Biotechnology). The
immunoprecipitated RB1 protein was separated on SDS-PAGE, and
subsequently transferred to a nitrocellulose membrane, which was
analyzed by BAS imaging system (BAS-TR2040, FUJI) or immunoblot
analysis.
Immunocytochemical Staining:
[0089] Cultured cells on chamber slides were fixed with PBS
containing 4% paraformaldehyde for 15 min, then rendered permeable
with PBS containing 0.1% Triton X-100 for 2.5 min at room
temperature. The cells were covered with 2% BSA in PBS for 24 h at
4.degree. C. to block non-specific hybridization, and then
incubated with anti-SMYD3 antibody, anti-RB [IF8] antibody and
anti-phospho RB (Thr 821/826) antibody as the first antibody. As
secondary antibody, fluorescent substrate-conjugated anti-rabbit or
anti-mouse IgG (Molecular probes) were used; nuclei were
counter-stained with 4', 6-diamidino-2-phenylindole dihydrochloride
(DAPI). Fluorescent images were obtained with TCS-SP2 confocal
microscope (Leica).
Luciferase Assay:
[0090] Luciferase assays were carried out using a Dual-Luciferase
Reporter Assay System according to the manufacturer's instructions
(Promega).
Cell Lines and Tissue Specimens:
[0091] Human embryonic kidney 293 (HEK293), HEK293T, and HEK293F
cells were purchased from IWAKI. A human hepatoma cell line HepG2,
and HCT116 and SW480 human colon cancer lines were obtained from
the American Type Culture Collection (ATCC). A human HCC cell line
SNU423 was a gift from the Korea cell-line bank. T47D and MCF7
breast cancer cell lines were kindly provided from the cancer
institute of the Japanese foundation for cancer research. All cell
lines were grown in monolayers in appropriate media. Primary breast
cancer tissues were obtained with informed consent from patients
(Hamamoto, R. et al. Cancer Sci 97, 113-118 (2006).).
Preparation of Plasmids:
[0092] Preparation of C-terminal FLAG-tagged SMYD3 was described
previously (Hamamoto, R. et al. Nat Cell Biol 6, 731-740 (2004).).
We additionally prepared plasmids expressing N-terminal HA-tagged,
or N-terminal 3.times.FLAG-tagged SMYD3 by cloning various PCR
products containing either wild-type or deleted forms of SMYD3 cDNA
into an appropriate site of pCMV-HA (Clontech) or p3XFLAG-CMV14
(Sigma) vector. Primers used for wild-type plasmids were
5'-AAGCTTGCGGCCGCGATGGAGCCGCTGAAGGTGGAAAAG-3' (SEQ ID NO: 5), and
5'-GGTACCTCTAGATTAGGATGCTCTGATGTTGGCGTC-3' (SEQ ID NO: 6), and
those used for mutants (FLAG-SMYD3-.DELTA.N44, -.DELTA.N99,
-.DELTA.N244, and -.DELTA.34) were
5'-GGGGTACCTTAGGATGCTCTGATGTTGGCGTC-3' (SEQ ID NO: 7) and
5'-CGGAATTCTGGCGCGATGGAGCCGCTGAAGGTGGAAAAG-3' (SEQ ID NO: 8),
5'-CGGAATTCTGACTCCGTTCGACTTCTTGGCAG-3' (SEQ ID NO: 9),
5'-CGGAATTCTCGGAAGCAGCTGAGGGACCAGTACTGC-3' (SEQ ID NO: 10), or
5'-CGGAATTCACCCTTGGCGTACACGGTGTGCAAGG-3' (SEQ ID NO: 11),
respectively. Mutant plasmids expressing substitution(s) at glycine
15, 17, or 27 were prepared using QuikChange II XL site-directed
mutagenesis Kit according to the supplier's protocol (Stratagene,
Calif., USA).
Western Blot Analysis:
[0093] A polyclonal antibody to SMYD3 was purified from sera of
rabbits immunized with a recombinant His-tagged SMYD3 protein
produced in E. coli as described elsewhere. Proteins were separated
by 10% SDS-PAGE and immunoblotted with anti-SMYD3, anti-HA (Sigma),
anti-FLAG (Sigma), anti-GST (Pharmingen), or anti-.beta.-actin
(Sigma) antibody. HRP-conjugated anti-rabbit IgG, anti-mouse IgG
(Amersham Biosciences), or anti-goat IgG (Santa Cruz) antibody
served as the secondary antibody for the ECL Detection System
(Amersham).
Determination of Cleavage Site:
[0094] C-terminal-FLAG-tagged SMYD3 was expressed exogenously in
293F cells. Immunoprecipitated SMYD3 protein with anti-FLAG
antibody from the cells was separated on duplicated SDS-PAGE gels,
and transferred to a nitrocellulose membrane and a sequence grade
PVDF membrane. The nitrocellulose membrane was used for immunoblot
analysis with anti-FLAG antibody to detect two forms of SMYD3
protein. After staining of the PVDF membrane with CBB solution
without acetic acid (0.025% CBB in 40% methanol), we excised the
band corresponding the short form of SMYD3 and subjected to amino
acid sequence. The amino acid sequence of the protein was
determined by Edman amino acid sequence method (Shimadzu
Biotechnologies, Tokyo, Japan).
In Vitro Histone Methyltransferase (HMTase) Assay:
[0095] FLAG-tagged SMYD3 was purified from 293T cells expressing
wild-type (p3XFLAG-CMV-SMYD3) or mutant SMYD3 (p3XFLAG-.DELTA.N34,
-.DELTA.N44, -SETNm1, -SETNm2 and -SETNm3) by immunoprecipitation
with anti-FLAG antibody. GST-fused SMYD3 proteins were purified
from bacterial cells expressing wild-type (GST-SMYD3-wt) or mutant
SMYD3 constructs (GST-SMYD3-.DELTA.N9, -.DELTA.N19, -.DELTA.N29,
-.DELTA.N44, -.DELTA.N74). In vitro HMTase assay was performed as
described elsewhere (Hamamoto, R. et al. Nat Cell Biol 6, 731-740
(2004).). 3H-radioactivity was measured by liquid scintillation
counter.
Example 1
RB1 as a Substrate for SMYD3
[0096] Since two recent reports showed that a histone H3-K4
methyltransferase SET7/9 catalyzes TAF10 and p53 as a substrates
(Chuikov, S. et al., Nature 432, 353-60 (2004)), the present
inventors searched for additional substrates for SMYD3 (GenBank
Accession NO. AB057595; SEQ ID NO; 1, 2) other than histone H3.
Because they are well known regulators of cell cycle progression,
p53 and RB1 were first tested (GenBank Accession NO.
NM.sub.--000321; SEQ ID NO; 3, 4) as candidate substrates. In the
course of investigation, recombinant histone H3, wild-type p53, and
C-terminal region of RB1 (codons 769-921) were incubated in the
presence of .sup.3H-labeled SAM, a methyl donor, together with
immunoprecipitated SMYD3 protein from 293T cells. Subsequent PAGE
and autoradiography showed bands corresponding methylated histone
H3, which is consistent with the finding that SMYD3 methylate
histone H3. Interestingly, bands corresponding to methylated RB1
were also detected; however, no bands corresponding to methylated
p53 were detected (FIG. 1a). The methyltransferase (MTase) activity
to histone H3 and the C-terminal RB1 was further measured using
recombinant SMYD3 protein. The results revealed a dose-dependent
increase of MTase activity on both substrates (FIG. 1b). Notably,
the MTase activity was higher to the C-terminal RB1 compared to
histone H3. It was further discovered that SET7/9 also has a
methyltransferase activity to RB1 (data not shown). In addition,
SMYD3 methylated full length of RB1 (FIG. 1c), suggesting that RB1
is methylated in vitro by SMYD3 as well as SET7/9, two histone
H3-K4 methyltransferases.
Example 2
The Methyltransferase Activity of SMYD3 on RB1 Proteins
[0097] To investigate a possible association between SMYD3 and RB1
proteins, proteins extracted from HepG2 or HCT116 cells were
immunoprecipitated with anti-SMYD3 antibody. As expected, bands
corresponding to RB1 protein were observed by immunoblot analysis
with anti-RB1 antibody (FIG. 2a). To determine the region of RB1
responsible for the association, Flag-tagged wild type or mutant
RB1 protein were expressed together with an HA-tagged SMYD3 in
HEK293 cells, and immunoprecipitation was carried out with an
anti-Flag antibody. In line with the methylation of C-terminal RB1
protein, the C-terminal substrate domain (codons 772-928)
interacted with SMYD3 (FIG. 2b). To determine the region of SMYD3
responsible for the binding with RB1, plasmids expressing wild type
and various forms of mutant SMYD3 were used. Although wild type,
and .DELTA.1-(codons 45-428) and .DELTA.2-forms (codons 1-250) of
mutant SMYD3 interacted with Flag-tagged RB1, .DELTA.3-form lacking
the SET domain (codons 1-100) did not interact with RB1, suggesting
that the SET domain is essential for the association (FIG. 2c). An
earlier report showed that histone H3-K9 methyltransferase SUV39H1
associates with RB and HP1, and the complex plays a role in
transcriptional suppression of cyclin E (Nielsen, S. J. et al.
Nature 412, 561-565 (2001).). Additionally, a recent study revealed
that activity of histone H4-K20 methyltransferases, Suv4-20h1 and
Suv4-20h2, was markedly enhanced through an interaction with RB1
(Gonzalo, S. et al. Nat Cell Biol 7, 420-428 (2005).). Therefore,
the present inventors tested whether RB1 enhances H3-K4
methyltransferase activity of SMYD3 or not. As a result,
SMYD3-mediated methylation of histone H3 was not affected by RB1
(FIG. 2d). Notably, SMYD3 did not show methyltransferase activity
to H3-K910 or H4-K20 (FIG. 2e). This data strengthens the
H3-K4-specific HMT (histone methyltransferase) activity of SMYD3,
and suggested that RB1 plays a role for histone modification in an
HMT-dependent fashion.
Example 3
Identification of the Methylation Substrate Domain of RB1
[0098] To determine the residue(s) responsible for the methylation
of the substrate domain of RB1, conserved amino acid sequences in
the substrates of SET7/9 methyltransferases were compared. Since
the methylated lysines were preceded by either serine or threonine,
the present inventors focused on lysine 824, lysine 889, and lysine
896 as candidates. Recombinant proteins, of wild type and three
forms of mutant substrate domain of RB1, were prepared (FIG. 3a).
Compared to the wild type protein, the K889A and K896A mutants were
methylated at similar levels by SMYD3 (FIG. 3b, c); however,
methylation of K824A was significantly decreased (FIG. 3b, c).
Additionally, because replacement of K824A did not completely
diminish methylation of RB1 protein, the methylation of lysine 791
and lysine 814, both of which are preceded by tyrosine, were
examined. Two mutant RB1 proteins, K791A and K814A, showed similar
levels of methylation to wild type-RB1 (FIG. 3d, e). Furthermore,
two forms of double-mutant RB1, K791A/K824A and K814A/K824A, showed
equivalent levels of methylation to the K824A protein. Hence, the
present inventors concluded that that lysine 824 is a major target
residue for the methylation. To confirm the methylation of lysine
824, methylated RB1-specific antibodies that recognize di- or
tri-methylated lysine 824 were prepared. In accordance with the
methylation of wild-type RB1 protein, the antibodies detected di-
and tri-methylated RB1 protein in immunoblot analysis (FIG. 3f) as
similar to that SMYD3 exerts di- and tri-methylation of histone H3
lysine 4 (Hamamoto, R. et al. Nat Cell Biol 6, 731-740 (2004).).
Although the methylated lysines in the substrates of SET7/9
including H3-K4, TAF10, and p53, were preceded by two conserved
peptides, R/K at the -2 position of lysine and S/T at the -1
position, the lysine 824 was preceded by P at the -2, and T at the
-1. Because RB1 is methylated by SMYD3 as well as SET7/9, R/K at
the -2 may not be essential but S/T at the -1 is indispensable for
the methylation by SMYD3 or SET7/9.
Example 4
In Vivo Methylation Assays
[0099] To further examine methylation of RB1 by SMYD3 in vivo, in
vivo methylation assays were carried out (Liu, Q. & Dreyfuss,
G. Mol Cell Biol 15, 2800-8 (1995)) using HEK293 cells that do not
express SMYD3. HEK293 cell lines expressing SMYD3 (HEK-SMYD3-1 and
-2) (FIG. 4a) were established and incubated the cells with
L-[methyl-.sup.3H] methionine in the presence of protein synthesis
inhibitors. Extracts from the cells were then immunopurified with
anti-RB1 monoclonal antibody, and the immunoprecipitated proteins
were analyzed by SDS-PAGE and subsequent autoradiography. Compared
to mock-transfected HEK293 cells (HEK-Mock-1 and -2), extracts from
HEK-SMYD3 (HEK-SMYD3-1 and -2) cells showed significantly stronger
bands corresponding to methylated RB1. Amount of immunoprecipitated
RB1 was unchanged among the cell lines (FIG. 4b). Consistently, an
increase in methylated RB1 was observed in HEK-SMYD3 cells as
compared to HEK-Mock cells by western blot analysis using
anti-pan-methyl-lysine, anti-di-methylated RB1-lysine 824, or
anti-tri-methylated RB1-lysine 824 antibodies (FIG. 4c).
Immunocytochemical staining of HEK-SMYD3 cells showed that cells
expressing abundant amount of SMYD3 were more strongly stained with
anti-di-methylated or anti-tri-methylated RB1-lysine 824 antibodies
(FIG. 4d-g, 4h-k, respectively) than those expressing a smaller
amount of SMYD3. This data corroborates the methylation of
RB1-lysine 824 by SMYD3 in vivo.
Example 5
In Vivo Phosphorylation Assays
[0100] The lysine 824 of RB1 is located between threonine
821.sup.st and 826.sup.th; residues phosphorylated by CDK/cyclin
complexes, and that regulate the interaction between RB1 and E2F
through the conformational change of central pocket domain. To
examine the effect of RB1 methylation on the phosphorylation of
these surrounding threonines, in vivo phosphorylation assays were
carried out using methylated or unmethylated RB1 protein.
Recombinant C-terminal RB1 was incubated with .sup.3H-labeled SAM
in the presence or absence of SMYD3, and then mixed with
.sup.32P-.gamma.ATP in combination with either recombinant
CDK2/CyclinE or CDK6/CyclinD3. Methylation and phosphorylation of
the recombinant RB1 was measured simultaneously by liquid
scintillation counter. The C-terminal RB1 protein incorporated four
to six fold higher amount of .sup.3H-labeled methyl donor in the
presence of SMYD3 than the absence of SMYD3 (data not shown).
Importantly, SMYD3 enhanced the phosphorylation of RB1 by
CDK2/CyclinE complex in a dose-dependent manner, while SMYD3 alone
did not increase the phosphorylation (FIG. 5a). In addition, it was
discovered that phosphorylation of RB1 is augmented by
CDK6/CyclinD3 in the presence of SMYD3 compared to the absence of
SMYD3 (FIG. 5b). However, phosphorylation of the K824A mutant RB1
by CDK2/Cyclin E or CDK6/Cyclin D3 was significantly suppressed,
compared to wild type RB1 (FIG. 5c, d, respectively). This data
suggests that phosphorylation of RB1 is enhanced through the
methylation of lysine 824 by SMYD3. Additional immunoblot analysis
using anti-phosphorylated RB1 antibody revealed that the
phosphorylation of threonine 821/826 was induced by SMYD3.
Interestingly, phosphorylation of serine 807/811 was also enhanced
by SMYD3 (FIG. 5e). Therefore, methylation of lysine 824 increase
the phosphorylation of serine 807/811, or additional methylated
residue(s) may enhance the phosphorylation.
[0101] To investigate enhanced phosphorylation of RB1 in vivo,
western blot analysis was carried out with anti-phosphorylated RB1
antibody using extracts from HEK-SMYD3 and HEK-Mock cells.
Consistent with the enhanced phosphorylation of RB1 protein in
vitro, elevated phosphorylation of both serine 807/811 and
threonine 821/826 was detected in HEK-SMYD cells as compared to the
control cells (FIG. 5f) Immunocytochemical staining using
anti-phosphorylated threonine 821/826 antibody and anti-SMYD3
antibody revealed that cells expressing SMYD3 were more strongly
stained with anti-phosphorylated threonine 821/826 antibody than
cells that do not express SMYD3 (FIG. 5g-j). In addition, exogenous
expression of wild type SMYD3 augmented di- and tri-methylation of
RB1 lysine 824 in SNU475 cells compared to that of mutant SMYD3
(SMYD3-.DELTA.EEL or SMYD3-.DELTA.NHSC) that lacks
methyltransferase activity (Hamamoto, R. et al. Nat Cell Biol 6,
731-40 (2004).). Correlated with the methylation of RB1 lysine 824,
we observed remarkable and moderate increase of phosphorylation at
threonines 821/826 and serines 807/811, respectively, in the cells
(FIG. 6a). Importantly, western blot analysis showed enhanced
methylation of RB1 lysine 824 together with increased
phosphorylation of serines 807/811 and threonines 821/826 in breast
cancer tissues that express augmented SMYD3 compared to
corresponding non-cancerous mammary tissues (FIG. 6b). This data
recapitulated the enhanced phosphorylation of serine 807/811 and
threonine 821/826 by SMYD3 in vivo. Since phosphorylation of RB1
modulates the pocket domain leading to dissociation of E2F from
RB1, reporter activity of E2F-mediated transcription was compared
in the HEK-SMYD3 cells using the Mercury.TM. cell cycle profiling
system. Compared with HEK-Mock cells, HEK-SMYD3 cells showed
elevated E2F transcriptional activity (FIG. 7). This data indicates
that SMYD3 enhances the phosphorylation of RB1 through methylation
of the lysine 824, which leads to elevated E2F transcriptional
activity.
Example 6
A Cleaved Form of SMYD3 Protein in Human Cancer Cells
[0102] We showed in our earlier studies that expression levels of
SMYD3 protein is elevated in human hepatocellular carcinoma (HCC),
colorectal carcinoma (CRC), and breast cancer (Hamamoto, R. et al.
Nat Cell Biol 6, 731-740 (2004), Hamamoto, R. et al. Cancer Sci 97,
113-118 (2006).). Interestingly, western blot analysis with
anti-SMYD3 antibody showed two bands of 45-kDa and 42-kDa in all
breast cancer tissues examined, but it detected neither of the two
bands in normal mammary gland. Both of 45-kDa and 42-kDa bands were
observed in HCC, CRC, and breast cancer cell lines (FIG. 8a) and
normal testis (data not shown). The predicted molecular weight of
SMYD3 was 45 kDa, and we did not find any altered forms of SMYD3
transcript in our RT-PCR analysis. Therefore, we hypothesized that
the 42-kDa band might result from cleavage of full-length SMYD3
protein. To examine the cleavage of SMYD3, we prepared plasmids
expressing N-terminal HA-tagged SMYD3 or C-terminal FLAG-tagged
SMYD3. Extracts of HEK293 cells expressing HA-tagged or FLAG-tagged
SMYD3 protein were used for immunoblot analysis with anti-HA or
anti-FLAG antibodies, respectively. As a result, we obtained 46-kDa
band of corresponding to the N-terminal HA-tagged protein with
anti-HA antibody. While we found two bands 46-kDa and 43-kDa
proteins with anti-FLAG antibody (FIG. 8b). This result suggested
that the full length protein was cleaved in its N-terminal region.
To investigate the cleavage site, we expressed exogenously
wild-type and deletion mutants of SMYD3 containing N-terminal
3.times.FLAG-tag in HEK293 cells that do not express endogenous
SMYD3 (FIG. 8c). Consistent the data of FIG. 8b, western blot
analysis with anti-FLAG antibody showed a band corresponding to the
48-kDa FLAG-tagged full-length protein alone in the cells
expressing wild-type SMYD3. However, analysis with anti-SMYD3
antibody using the same extract detected two bands corresponding to
the 48-kDa FLAG-tagged SMYD3 and 42-kDa protein. Western blot
analysis with anti-SMYD3 antibody using extracts from cells
expressing N-terminal deleted forms of SMYD3
(FLAG-SMYD3-.DELTA.N44, -.DELTA.N99, and -.DELTA.N244) showed
single bands. These data suggested that the cleavage site of SMYD3
localized between codons 1 and 45.
Example 7
Determination of Cleavage Site of SMYD3 Protein
[0103] In an attempt to determine the exact cleavage site of SMYD3,
we purified the 42-kDa protein from PVDF-membrane transferred with
immunoprecipitated FLAG-tagged SMYD3 protein (FIG. 8b), and
determined its amino acid sequence. As a result, we identified a
deleted form of SMYD3 protein lacking N-terminal 34-amino acids,
which revealed a cleavage site between codon 34 (aspartic acid) and
codon 35 (proline) (FIG. 9a). SMYD3 contains an amino acid sequence
termed SET-N region between codons 5 and 27, which is conserved in
SET domain proteins (Marmorstein, R. Trends in Biochem. Sci., Vol.
8 no. 2, (2003); Kouzarides, T. Curr. Opin. Genet. Dev. 12, 198-209
(2002); Lachner, M. and Jenuwein, T. Curr. Opin. Cell biol. 14,
286-298 (2002)). An alignment of amino acid sequences of SET-N
region depicted the high similarity of the region in SMYD3 and
other methyltransferases (FIG. 9b), implying the importance of this
region.
Example 8
Increased HMTase Activity of the Cleaved SMYD3 Compared with the
Wild Type Protein
[0104] To investigate the methyltransferase activity of the cleaved
SMYD3 protein, we expressed 3.times.FLAG-tagged wild-type, or 34-
or 44-amino acids-deleted forms of SMYD3 exogenously in HEK293
cells, and immunoprecipitated these proteins (FIG. 10a). We carried
out a histone methyltransferase (HMTase) assay using these proteins
as an enzyme source, and Showed that HMTase activity of the
wild-type SMYD3 increased in a dose-dependent manner (FIG. 10b).
Reaction of methylation in the presence of a methyl donor,
S-adenosyl methionine (SAM), accompanies production of S-adenosyl
homocysteine (SAH), which may inhibit the methyltransferase
reaction in a competitive manner. Therefore we added, in the
reaction mixture, S-adenosyl homocysteine hydrolase (SAHH) that
hydrolyzes SAH to homocysteine and adenosine. As expected, we
observed striking increase of HMT activity in the presence of SAHH
compared to its absence (FIG. 10b). This finding is useful for the
screening of methyltransferase inhibitor(s) of SMYD3. Surprisingly,
the cleaved SMYD3 proteins had significantly higher HMTase activity
compared to the full-length protein (FIG. 10b). This result
indicates that post-translational cleavage is involved in the
regulation of SMYD3 HMTase activity in human cells, and that the
N-terminal SET-N region may have a suppressive role for the HMTase
activity
Example 9
Glycine 15 and 17 in the SET-N Region is Important for the HMT
Activity
[0105] To determine the importance of the conserved amino acid
sequence in the SET-N region for the suppressed enzyme activity, we
prepared plasmids expressing wild-type or mutant N-terminal
FLAG-tagged SMYD3 protein, SMYD3-SETNm1, -SETNm2, or -SETNm3,
containing substitution(s) of both Gly15Ala and Gly17Ala, Gly15Ala,
or Gly27Ala, respectively (FIG. 11a). Western blot of the lysates
from HEK293 cells expressing these mutants showed that the
substitutions did not affect the cleavage of SMYD3 protein (FIG.
11b, upper panel). We performed HMTase assay using
immunoprecipitated SMYD3 protein. As a result, mutant proteins
containing either Gly15Ala or Gly27Ala (SMYD3-SETNm2 or -SETNm3)
had similar HMTase activity to wild-type protein (FIG. 11c).
Whereas a mutant protein containing two substitutions of Gly15Ala
and Gly17Ala (SMYD3-SETNm1) showed significantly enhanced activity
compared to the wild-type protein (FIG. 11c). These data suggest
that glycines 15 and 17 may play an important role for the
regulation of HMTase activity of SMYD3.
Example 10
Deletion of N-Terminal 10 Amino Acids is Critical for the Enhanced
HMTase Activity
[0106] Since the N-terminal region enhanced its enzymatic activity,
we hypothesized two possible mechanisms; the N-terminal region
might associate with undetermined negative regulatory factor(s) for
the enzyme activity, or the deletion might confer conformational
change of the protein leading to enhanced enzyme activity. To
determine whether additional negative regulatory factor(s) may play
a role in the enzyme activity, we prepared recombinant proteins of
wild-type and N-terminal deleted SMYD3, and investigated their
HMTase activity in vitro. As shown in FIG. 12, all deletions
mutants (SMYD3-.DELTA.N9, -.DELTA.N19, -.DELTA.N29, -.DELTA.N44,
-.DELTA.N74) exhibited four to five fold enhanced methyltransferase
activity compared to the wild-type protein (FIG. 12). This result
suggests that additional factor is not likely to be involved in the
elevated activity of the cleaved SMYD3, and that the N-terminal
ten-amino-acids may play a crucial role for the suppression of
methyltransferase activity.
Discussion
[0107] Disclosed herein is the finding that SMYD3 has a
methyltransferase activity on lysine 824 of RB1 in vitro and in
vivo, and that the methylated RB1 is more susceptible for
phosphorylation by CDK/cyclin complex than unmethylated RB1.
Consequently, HEK293-SMYD3 cells expressing SMYD3 showed elevated
E2F-transcriptional activity compared to HEK293-Mock cells, which
is in good agreement with growth-promoting effect of SMYD3, because
E2F-1 overexpression can promoter transition from the G1 phase to
the S phase of the cell cycle by regulating a series of genes whose
products are essential for cell proliferation. Harbour et al.
presented a model of RB1 phosphorylation during the G1-S
progression, in which phosphorylation of RB1 initiates sequential
intramolecular interaction between the C-terminal region and the
pocket domain (Harbour, J. W. et al., D. C. Cell 98, 859-69
(1999)). During the G1 phase, phosphorylation of the C-terminal
region of RB1 by CDK4/6-cyclin D triggers intramolecular
interaction with the central pocket domain, which inhibits HDAC
binding, thereby blocking active transcriptional repression. The
interaction facilitates accession of CDK2/cyclin E to serine 567 of
RB1, which, in turn, results in disruption of the A/B interface and
preventing the RB1 interaction with E2F. In this model, successive
phosphorylation of RB1 by both CDK4/6-cyclinD and CDK2/cyclin E
complexes is required for the dissociation of E2F (Lundberg, A. S.
& Weinberg, R. A. Mol Cell Biol 18, 753-61 (1998)). Reportedly,
phosphorylation of Thr821 and Thr826 in RB1 inactivates the
interaction between the A/B pocket domain and LXCXE
motif-containing proteins including E2Fs and HDACs, while
phosphorylation of Ser807 and Ser811 inactivates the C-terminal
domain. This data agrees with the instant discovery that cells
expressing SMYD3 show higher E2F transcriptional activity, as
methylation of RB1 by SMYD3 enhanced the phosphorylation by
CDK2/cyclin E or CDK6/cyclin D complexes, and phosphorylation of
Thr821/826 is elevated. Alternatively, methylation of lysine 824
may directly change the conformation of the C-terminal region, and
thereby inhibit the association of the pocket domain with E2F,
because lysine methylation of both histones and p53 leads to their
conformational change (Tsuge, M. et al. Nat Genet. 37, 1104-7
(2005)). Since SMYD3 increases the transcriptional activity of E2F,
elevated SMYD3 may enhance E2F1 activity as a positive feedback
mechanism. Hence SMYD3-mediated RB1 inactivation is likely to play
a crucial role in human carcinogenesis.
[0108] It is of note that RB1 plays a role in transcriptional
repression through several mechanisms; RB1 interacts with
transcription factors and directly suppresses their activity;
recruitment of RB1 into the promoter region blocks the assembly of
pre-initiation complexes; it also associates with class I HDACs
(HDAC-1, -2, and -3), and induces the deacetylation of histories,
resulting in conformational change to heterochromatin state; it
forms a complex with DNMT1 leading to the DNA methylation in
promoter region of target genes (Harbour, J. W. & Dean, D. C.
Genes Dev 14, 2393-409 (2000); Robertson, K. D. et al. Nat Genet.
25, 338-42 (2000)). In addition to these mechanisms, recent studies
on histone methylation disclosed that RB1 also associates with
histone methyltransferases including SUV39H, and Suv4-20h1 or
Suv4-20h1, which are involved in H3-K9 and H4-K20 methylation,
respectively (Gonzalo, S. et al. Nat Cell Biol 7, 420-8 (2005);
Nielsen, S. J. et al. Nature 412, 561-5 (2001)). Bound to these
methyltransferases, RB1 stabilizes heterochromatin formation by
recruiting HP1 or CBX into the complex. The instant findings bring
a novel insight into the regulation of transcriptional activation
of histone H3-K4 methyltransferase. Methylated RB1 at lysine 824
enhances phosphorylation of RB1 and subsequent transactivation of
E2F1 by presumably releasing it from the central pocket domain. In
addition, methylated RB1 may change its conformation and thereby
dissociate HDACs, heterochromatin protein 1 (HP1), and/or chromobox
proteins (CBXs) from the complex of SUV39H and/or Suv4-20h1
methyltransferases, leading to the reduced methylation of H3-K9 and
H4-K20. Although further investigation is warranted, the data
herein highlight the importance of methylation of RB1 in the
regulation of E2F responsible genes. Since RB1 binds to different
methyltransferases, position and degree of methylation in RB1 may
differ by the methyltransferases. Taken together that RB1 is also
phosphorylated at different residues, the data herein suggest that
a combination of multiple modifications in RB1 may define its
biological properties, which is reminiscent of modification of
histones and p53.
[0109] Mutation of RB1 is involved in not only sporadic and
familial cases of retinoblastoma (Weinberg, R. A. Science 254,
1138-46 (1991)), but also other human cancers (Classon, M. &
Harlow, E. Nat Rev Cancer 2, 910-7 (2002)). Several oncogenic viral
proteins such as adenovirus E1A, HPV-E7, and simian virus 40 (SV40)
large T antigen associate with RB1 in some types of cancers, which
inhibits the interaction between RB1 and E2F leading to
dissociation of E2F (Chellappan, S. P., et al. Cell 65, 1053-61
(1991); Bagchi, S., et al. Cell 65, 1063-72 (1991)). p16, an
inhibitor of cyclin-dependent kinase 4, is frequently inactivated
by methylation of its promoter, resulting in enhanced
phosphorylation of RB1 by CDK/cyclin complexes in cancer cells
(Nuovo, G. J., et al. Proc Natl Acad Sci USA 96, 12754-9 (1999)).
These defects are reported to be involved in a part of colorectal
and hepatocellular carcinomas (Chaubert, P. et al. Hepatology 25,
1376-81 (1997); Toyota, M. et al. Proc Natl Acad Sci USA 96, 8681-6
(1999)), and may not account for all cases in these types of
tumors. Herein, a novel mechanism for inactivation of RB1 is
disclosed, namely one that is caused by the methylation and
subsequent enhanced phosphorylation of RB1. Since expression of
SMYD3 is enhanced in the majority of colorectal and hepatocellular
carcinomas, SMYD3 may play a crucial role in the proliferation of
cancer cells by transactivation of E2F through abrogated RB1 tumor
suppressor function. Interestingly, the present inventors recently
discovered that SMYD3 expression is regulated by E2F-1 through its
interaction to an E2F-1 binding element in the promoter region of
SMYD3, and that the element comprises of two- or three-tandem
repeats of E2F-1 binding motif. Allele frequency of the
three-repeats in Japanese colorectal (n=350), liver (n=360), and
breast (n=334) cancer patients was significantly higher than that
in healthy controls (n=730) from general Japanese population. This
data suggests that once SMYD3 is activated, it enhances E2F
transcriptional activity through the modification of RB1, and
consequently up-regulates SMYD3 by a positive feedback. Therefore,
people containing three-repeats of E2F-1 binding element are more
susceptible for the inactivation of RB1 by SMYD3 than those
containing two-repeats. Additionally, the inhibition of SMYD3
appears to be a promising therapeutic strategy for colorectal and
liver cancers, as well as bladder and breast cancers, because it
will block the positive feedback loop, thereby efficiently suppress
the E2F-1-mediated mitogenic activity by phosphorylation of
RB1.
[0110] Herein, it was revealed that methylation of RB1 by SMYD3 may
accelerates cell cycle progression from G1 to S phase through the
enhanced phosphorylation of RB1 by CDK/cyclin complexes. This data
indicates that methylation of lysine is important for not only
histones but also other non-histone proteins, such as p53 and RB1.
In addition, our findings have shed light on the novel mechanism of
RB1 regulation that is involved in human carcinogenesis.
[0111] It has been shown that perturbation of epigenetic regulation
is associated with human carcinogenesis. In addition to the
abnormal DNA methylation in the promoter region of genes regulating
cell cycle, DNA repair, and cell adhesion, recent investigations
disclosed that histone methylation is also abrogated in human
carcinogenesis. Histone methylation plays a crucial role in the
regulation of gene expression through the change of chromatin
structure. We reported that SMYD3, a histone H3-Lysine 4-specific
methyltransferase, is over-expressed in several human cancers
including HCC, CRC and breast carcinoma (Hamamoto, R. et al. Nat
Cell Biol 6, 731-740 (2004): Hamamoto, R. et al. Cancer Sci 97,
113-118 (2006).). In our previous paper, we showed that its
expression is elevated by transcriptional activation of E2F1, a
transcription factor that is frequently enhanced in a variety of
human cancer.
[0112] Protein function is regulated not only at
post-transcriptional levels, but also by posttranslational
modifications, which include cleavage of protein and other wide
known modifications such as acetylation, phosphorylation,
methylation, glycosylation and ubiquitination. These modifications
are associated with protein stability, conformation of protein,
and/or protein-protein interactions resulting in activation or
inactivation of the protein. We have found that cleavage of SMYD3
increases its HMTase activity, which is reminiscent of regulation
of critical enzymes such as pepsin, insulin, caspases, PARD, and
MMPs, since cleavage of these proteins increases their enzymatic
activity. This finding additionally suggests that an undetermined
mechanism of the cleavage of SMYD3 may play a role in the
modulation of HMTase activity. Therefore identification of the
protease responsible for the cleavage, and clarification of the
regulatory mechanism(s) will contribute to the development of novel
therapeutic approaches to suppress SMYD3 activity. Furthermore a
cleaved form of SMYD3 may be useful for the screening of SMYD3
inhibitors compared to full-length protein.
[0113] We have found in this study that loss of SMYD3 N-terminal
region enhances its enzyme activity in vitro, suggesting that the
deletion might confer conformational change of SMYD3 leading to the
enhanced enzyme activity. Interestingly, HSP90 binds to N-terminal
region of SMYD3 resulting in an increase of its HMTase activity.
This data is in good agreement with the view that conformational
change is involved in the HMTase activity, because HSP90 exerts a
chaperone-like function contributing to stabilizing normal protein
structure. Our findings also underscore the importance of the
conserved SET-N region for regulation of HMTase activity. This
conserved region may also act as a negative regulator of HMTases in
other SET domain containing proteins. Further studies will uncover
the mechanisms of regulation of HMTase activity in SET domain
containing proteins.
[0114] We have shown here that an N-terminal cleaved form of SMYD3
protein is expressed in cancer cells and that the cleaved protein
has markedly higher HMTase activity than full-length protein. These
data implied that a post-translational regulatory system regulates
the HMTase activity through a possible conformational change of the
protein. Furthermore, we have found that an addition of SAHH
increases the methyltransferase activity of SMYD3. Our findings
will help for the better understanding of the regulatory mechanisms
of SMYD3 activity, and may contribute to the identification of
novel therapeutic strategies to inhibit the HMTase activity.
INDUSTRIAL APPLICABILITY
[0115] The methods described herein are useful in the
identification of additional molecular targets for prevention,
diagnosis and treatment of various cancers, including colorectal
cancer, hepatocellular cancer, breast cancer and bladder cancer.
Furthermore, the data reported herein add to a comprehensive
understanding of cancer, facilitate development of novel diagnostic
strategies, and provide clues for identification of molecular
targets for therapeutic drugs and preventative agents. Such
information contributes to a more profound understanding of
tumorigenesis, and provides indicators for developing novel
strategies for diagnosis, treatment, and ultimately prevention of
cancer. While the present invention has been described in detail
and with reference to specific embodiments thereof, it is to be
understood that the foregoing description is exemplary and
explanatory in nature and is intended to illustrate the invention
and its preferred embodiments. Through routine experimentation, one
skilled in the art will readily recognize that various changes and
modifications can be made therein without departing from the spirit
and scope of the invention. Thus, the invention is intended to be
defined not by the above description, but by the following claims
and their equivalents.
Sequence CWU 1
1
3811622DNAHomo sapiensSET and MYND domain containing 3 (SMYD3),
zinc finger protein, subfamily 3A (MYND domain containing) 1
(ZNFN3A1), zinc finger MYND domain-containing protein 1 (ZMYND1),
histone H3-lysine 4-specific methyltransferase cDNA 1gtgcgcgcag
ggcgcaggcg cgcgggtccc ggcagcccgt gagacgcccg ctgctggacg 60cgggtagccg
tctgaggtgc cggagctgcg ggagg atg gag ccg ctg aag gtg 113 Met Glu Pro
Leu Lys Val 1 5gaa aag ttc gca acc gcc aac agg gga aac ggg ctg cgc
gcc gtg acc 161Glu Lys Phe Ala Thr Ala Asn Arg Gly Asn Gly Leu Arg
Ala Val Thr 10 15 20ccg ctg cgc ccc gga gag cta ctc ttc cgc tcg gat
ccc ttg gcg tac 209Pro Leu Arg Pro Gly Glu Leu Leu Phe Arg Ser Asp
Pro Leu Ala Tyr 25 30 35acg gtg tgc aag ggg agt cgt ggc gtc gtc tgc
gac cgc tgc ctt ctc 257Thr Val Cys Lys Gly Ser Arg Gly Val Val Cys
Asp Arg Cys Leu Leu 40 45 50ggg aag gaa aag ctg atg cga tgc tct cag
tgc cgc gtc gcc aaa tac 305Gly Lys Glu Lys Leu Met Arg Cys Ser Gln
Cys Arg Val Ala Lys Tyr55 60 65 70tgt agt gct aag tgt cag aaa aaa
gct tgg cca gac cac aag cgg gaa 353Cys Ser Ala Lys Cys Gln Lys Lys
Ala Trp Pro Asp His Lys Arg Glu 75 80 85tgc aaa tgc ctt aaa agc tgc
aaa ccc aga tat cct cca gac tcc gtt 401Cys Lys Cys Leu Lys Ser Cys
Lys Pro Arg Tyr Pro Pro Asp Ser Val 90 95 100cga ctt ctt ggc aga
gtt gtc ttc aaa ctt atg gat gga gca cct tca 449Arg Leu Leu Gly Arg
Val Val Phe Lys Leu Met Asp Gly Ala Pro Ser 105 110 115gaa tca gag
aag ctt tac tca ttt tat gat ctg gag tca aat att aac 497Glu Ser Glu
Lys Leu Tyr Ser Phe Tyr Asp Leu Glu Ser Asn Ile Asn 120 125 130aaa
ctg act gaa gat aag aaa gag ggc ctc agg caa ctc gta atg aca 545Lys
Leu Thr Glu Asp Lys Lys Glu Gly Leu Arg Gln Leu Val Met Thr135 140
145 150ttt caa cat ttc atg aga gaa gaa ata cag gat gcc tct cag ctg
cca 593Phe Gln His Phe Met Arg Glu Glu Ile Gln Asp Ala Ser Gln Leu
Pro 155 160 165cct gcc ttt gac ctt ttt gaa gcc ttt gca aaa gtg atc
tgc aac tct 641Pro Ala Phe Asp Leu Phe Glu Ala Phe Ala Lys Val Ile
Cys Asn Ser 170 175 180ttc acc atc tgt aat gcg gag atg cag gaa gtt
ggt gtt ggc cta tat 689Phe Thr Ile Cys Asn Ala Glu Met Gln Glu Val
Gly Val Gly Leu Tyr 185 190 195ccc agt atc tct ttg ctc aat cac agc
tgt gac ccc aac tgt tcg att 737Pro Ser Ile Ser Leu Leu Asn His Ser
Cys Asp Pro Asn Cys Ser Ile 200 205 210gtg ttc aat ggg ccc cac ctc
tta ctg cga gca gtc cga gac atc gag 785Val Phe Asn Gly Pro His Leu
Leu Leu Arg Ala Val Arg Asp Ile Glu215 220 225 230gtg gga gag gag
ctc acc atc tgc tac ctg gat atg ctg atg acc agt 833Val Gly Glu Glu
Leu Thr Ile Cys Tyr Leu Asp Met Leu Met Thr Ser 235 240 245gag gag
cgc cgg aag cag ctg agg gac cag tac tgc ttt gaa tgt gac 881Glu Glu
Arg Arg Lys Gln Leu Arg Asp Gln Tyr Cys Phe Glu Cys Asp 250 255
260tgt ttc cgt tgc caa acc cag gac aag gat gct gat atg cta act ggt
929Cys Phe Arg Cys Gln Thr Gln Asp Lys Asp Ala Asp Met Leu Thr Gly
265 270 275gat gag caa gta tgg aag gaa gtt caa gaa tcc ctg aaa aaa
att gaa 977Asp Glu Gln Val Trp Lys Glu Val Gln Glu Ser Leu Lys Lys
Ile Glu 280 285 290gaa ctg aag gca cac tgg aag tgg gag cag gtt ctg
gcc atg tgc cag 1025Glu Leu Lys Ala His Trp Lys Trp Glu Gln Val Leu
Ala Met Cys Gln295 300 305 310gca atc ata agc agc aat tct gaa cgg
ctt ccc gat atc aac atc tac 1073Ala Ile Ile Ser Ser Asn Ser Glu Arg
Leu Pro Asp Ile Asn Ile Tyr 315 320 325cag ctg aag gtg ctc gac tgc
gcc atg gat gcc tgc atc aac ctc ggc 1121Gln Leu Lys Val Leu Asp Cys
Ala Met Asp Ala Cys Ile Asn Leu Gly 330 335 340ctg ttg gag gaa gcc
ttg ttc tat ggt act cgg acc atg gag cca tac 1169Leu Leu Glu Glu Ala
Leu Phe Tyr Gly Thr Arg Thr Met Glu Pro Tyr 345 350 355agg att ttt
ttc cca gga agc cat ccc gtc aga ggg gtt caa gtg atg 1217Arg Ile Phe
Phe Pro Gly Ser His Pro Val Arg Gly Val Gln Val Met 360 365 370aaa
gtt ggc aaa ctg cag cta cat caa ggc atg ttt ccc caa gca atg 1265Lys
Val Gly Lys Leu Gln Leu His Gln Gly Met Phe Pro Gln Ala Met375 380
385 390aag aat ctg aga ctg gct ttt gat att atg aga gtg aca cat ggc
aga 1313Lys Asn Leu Arg Leu Ala Phe Asp Ile Met Arg Val Thr His Gly
Arg 395 400 405gaa cac agc ctg att gaa gat ttg att cta ctt tta gaa
gaa tgc gac 1361Glu His Ser Leu Ile Glu Asp Leu Ile Leu Leu Leu Glu
Glu Cys Asp 410 415 420gcc aac atc aga gca tcc taa gggaacgcag
tcagagggaa atacggcgtg 1412Ala Asn Ile Arg Ala Ser 425tgtctttgtt
gaatgcctta ttgaggtcac acactctatg ctttgttagc tgtgtgaacc
1472tctcctattg gaaattctgt tccgtgtttg tgtaggtaaa taaaggcaga
catggtttgc 1532aaaccacaag aatcattagt tgtagagaag cacgattata
ataaattcaa aacatttggt 1592tgaggatgcc aaaaaaaaaa aaaaaaaaaa
16222428PRTHomo sapiensSET and MYND domain containing 3 (SMYD3),
zinc finger protein, subfamily 3A (MYND domain containing) 1
(ZNFN3A1), zinc finger MYND domain-containing protein 1 (ZMYND1),
histone H3-lysine 4-specific methyltransferase 2Met Glu Pro Leu Lys
Val Glu Lys Phe Ala Thr Ala Asn Arg Gly Asn1 5 10 15 Gly Leu Arg
Ala Val Thr Pro Leu Arg Pro Gly Glu Leu Leu Phe Arg 20 25 30 Ser
Asp Pro Leu Ala Tyr Thr Val Cys Lys Gly Ser Arg Gly Val Val 35 40
45 Cys Asp Arg Cys Leu Leu Gly Lys Glu Lys Leu Met Arg Cys Ser Gln
50 55 60 Cys Arg Val Ala Lys Tyr Cys Ser Ala Lys Cys Gln Lys Lys
Ala Trp65 70 75 80 Pro Asp His Lys Arg Glu Cys Lys Cys Leu Lys Ser
Cys Lys Pro Arg 85 90 95 Tyr Pro Pro Asp Ser Val Arg Leu Leu Gly
Arg Val Val Phe Lys Leu 100 105 110 Met Asp Gly Ala Pro Ser Glu Ser
Glu Lys Leu Tyr Ser Phe Tyr Asp 115 120 125 Leu Glu Ser Asn Ile Asn
Lys Leu Thr Glu Asp Lys Lys Glu Gly Leu 130 135 140 Arg Gln Leu Val
Met Thr Phe Gln His Phe Met Arg Glu Glu Ile Gln145 150 155 160 Asp
Ala Ser Gln Leu Pro Pro Ala Phe Asp Leu Phe Glu Ala Phe Ala 165 170
175 Lys Val Ile Cys Asn Ser Phe Thr Ile Cys Asn Ala Glu Met Gln Glu
180 185 190 Val Gly Val Gly Leu Tyr Pro Ser Ile Ser Leu Leu Asn His
Ser Cys 195 200 205 Asp Pro Asn Cys Ser Ile Val Phe Asn Gly Pro His
Leu Leu Leu Arg 210 215 220 Ala Val Arg Asp Ile Glu Val Gly Glu Glu
Leu Thr Ile Cys Tyr Leu225 230 235 240 Asp Met Leu Met Thr Ser Glu
Glu Arg Arg Lys Gln Leu Arg Asp Gln 245 250 255 Tyr Cys Phe Glu Cys
Asp Cys Phe Arg Cys Gln Thr Gln Asp Lys Asp 260 265 270 Ala Asp Met
Leu Thr Gly Asp Glu Gln Val Trp Lys Glu Val Gln Glu 275 280 285 Ser
Leu Lys Lys Ile Glu Glu Leu Lys Ala His Trp Lys Trp Glu Gln 290 295
300 Val Leu Ala Met Cys Gln Ala Ile Ile Ser Ser Asn Ser Glu Arg
Leu305 310 315 320 Pro Asp Ile Asn Ile Tyr Gln Leu Lys Val Leu Asp
Cys Ala Met Asp 325 330 335 Ala Cys Ile Asn Leu Gly Leu Leu Glu Glu
Ala Leu Phe Tyr Gly Thr 340 345 350 Arg Thr Met Glu Pro Tyr Arg Ile
Phe Phe Pro Gly Ser His Pro Val 355 360 365 Arg Gly Val Gln Val Met
Lys Val Gly Lys Leu Gln Leu His Gln Gly 370 375 380 Met Phe Pro Gln
Ala Met Lys Asn Leu Arg Leu Ala Phe Asp Ile Met385 390 395 400 Arg
Val Thr His Gly Arg Glu His Ser Leu Ile Glu Asp Leu Ile Leu 405 410
415 Leu Leu Glu Glu Cys Asp Ala Asn Ile Arg Ala Ser 420 425
34740DNAHomo sapiensretinoblastoma 1 protein (RB1), retinoblastoma
susceptibility protein, OSRC. p105-Rb, pRb, RB 3ttccggtttt
tctcagggga cgttgaaatt atttttgtaa cgggagtcgg gagaggacgg 60ggcgtgcccc
gcgtgcgcgc gcgtcgtcct ccccggcgct cctccacagc tcgctggctc
120ccgccgcgga aaggcgtc atg ccg ccc aaa acc ccc cga aaa acg gcc gcc
171 Met Pro Pro Lys Thr Pro Arg Lys Thr Ala Ala 1 5 10acc gcc gcc
gct gcc gcc gcg gaa ccc ccg gca ccg ccg ccg ccg ccc 219Thr Ala Ala
Ala Ala Ala Ala Glu Pro Pro Ala Pro Pro Pro Pro Pro 15 20 25cct cct
gag gag gac cca gag cag gac agc ggc ccg gag gac ctg cct 267Pro Pro
Glu Glu Asp Pro Glu Gln Asp Ser Gly Pro Glu Asp Leu Pro 30 35 40ctc
gtc agg ctt gag ttt gaa gaa aca gaa gaa cct gat ttt act gca 315Leu
Val Arg Leu Glu Phe Glu Glu Thr Glu Glu Pro Asp Phe Thr Ala 45 50
55tta tgt cag aaa tta aag ata cca gat cat gtc aga gag aga gct tgg
363Leu Cys Gln Lys Leu Lys Ile Pro Asp His Val Arg Glu Arg Ala
Trp60 65 70 75tta act tgg gag aaa gtt tca tct gtg gat gga gta ttg
gga ggt tat 411Leu Thr Trp Glu Lys Val Ser Ser Val Asp Gly Val Leu
Gly Gly Tyr 80 85 90att caa aag aaa aag gaa ctg tgg gga atc tgt atc
ttt att gca cga 459Ile Gln Lys Lys Lys Glu Leu Trp Gly Ile Cys Ile
Phe Ile Ala Arg 95 100 105gtt gac cta gat gag atg tcg ttc act tta
ctg agc tac aga aaa aca 507Val Asp Leu Asp Glu Met Ser Phe Thr Leu
Leu Ser Tyr Arg Lys Thr 110 115 120tac gaa atc agt gtc cat aaa ttc
ttt aac tta cta aaa gaa att gat 555Tyr Glu Ile Ser Val His Lys Phe
Phe Asn Leu Leu Lys Glu Ile Asp 125 130 135acc agt acc aaa gtt gat
aat gct atg tca aga ctg ttg aag aag tat 603Thr Ser Thr Lys Val Asp
Asn Ala Met Ser Arg Leu Leu Lys Lys Tyr140 145 150 155gat gta ttg
ttt gca ctc ttc agc aaa ttg gaa agg aca tgt gaa ctt 651Asp Val Leu
Phe Ala Leu Phe Ser Lys Leu Glu Arg Thr Cys Glu Leu 160 165 170ata
tat ttg aca caa ccc agc agt tcg ata tct act gaa ata aat tct 699Ile
Tyr Leu Thr Gln Pro Ser Ser Ser Ile Ser Thr Glu Ile Asn Ser 175 180
185gca ttg gtg cta aaa gtt tct tgg atc aca ttt tta tta gct aaa ggg
747Ala Leu Val Leu Lys Val Ser Trp Ile Thr Phe Leu Leu Ala Lys Gly
190 195 200gaa gta tta caa atg gaa gat gat ctg gtg att tca ttt cag
tta atg 795Glu Val Leu Gln Met Glu Asp Asp Leu Val Ile Ser Phe Gln
Leu Met 205 210 215cta tgt gtc ctt gac tat ttt att aaa ctc tca cct
ccc atg ttg ctc 843Leu Cys Val Leu Asp Tyr Phe Ile Lys Leu Ser Pro
Pro Met Leu Leu220 225 230 235aaa gaa cca tat aaa aca gct gtt ata
ccc att aat ggt tca cct cga 891Lys Glu Pro Tyr Lys Thr Ala Val Ile
Pro Ile Asn Gly Ser Pro Arg 240 245 250aca ccc agg cga ggt cag aac
agg agt gca cgg ata gca aaa caa cta 939Thr Pro Arg Arg Gly Gln Asn
Arg Ser Ala Arg Ile Ala Lys Gln Leu 255 260 265gaa aat gat aca aga
att att gaa gtt ctc tgt aaa gaa cat gaa tgt 987Glu Asn Asp Thr Arg
Ile Ile Glu Val Leu Cys Lys Glu His Glu Cys 270 275 280aat ata gat
gag gtg aaa aat gtt tat ttc aaa aat ttt ata cct ttt 1035Asn Ile Asp
Glu Val Lys Asn Val Tyr Phe Lys Asn Phe Ile Pro Phe 285 290 295atg
aat tct ctt gga ctt gta aca tct aat gga ctt cca gag gtt gaa 1083Met
Asn Ser Leu Gly Leu Val Thr Ser Asn Gly Leu Pro Glu Val Glu300 305
310 315aat ctt tct aaa cga tac gaa gaa att tat ctt aaa aat aaa gat
cta 1131Asn Leu Ser Lys Arg Tyr Glu Glu Ile Tyr Leu Lys Asn Lys Asp
Leu 320 325 330gat cga aga tta ttt ttg gat cat gat aaa act ctt cag
act gat tct 1179Asp Arg Arg Leu Phe Leu Asp His Asp Lys Thr Leu Gln
Thr Asp Ser 335 340 345ata gac agt ttt gaa aca cag aga aca cca cga
aaa agt aac ctt gat 1227Ile Asp Ser Phe Glu Thr Gln Arg Thr Pro Arg
Lys Ser Asn Leu Asp 350 355 360gaa gag gtg aat ata att cct cca cac
act cca gtt agg act gtt atg 1275Glu Glu Val Asn Ile Ile Pro Pro His
Thr Pro Val Arg Thr Val Met 365 370 375aac act atc caa caa tta atg
atg att tta aat tct gca agt gat caa 1323Asn Thr Ile Gln Gln Leu Met
Met Ile Leu Asn Ser Ala Ser Asp Gln380 385 390 395cct tca gaa aat
ctg att tcc tat ttt aac aac tgc aca gtg aat cca 1371Pro Ser Glu Asn
Leu Ile Ser Tyr Phe Asn Asn Cys Thr Val Asn Pro 400 405 410aaa gaa
agt ata ctg aaa aga gtg aag gat ata gga tac atc ttt aaa 1419Lys Glu
Ser Ile Leu Lys Arg Val Lys Asp Ile Gly Tyr Ile Phe Lys 415 420
425gag aaa ttt gct aaa gct gtg gga cag ggt tgt gtc gaa att gga tca
1467Glu Lys Phe Ala Lys Ala Val Gly Gln Gly Cys Val Glu Ile Gly Ser
430 435 440cag cga tac aaa ctt gga gtt cgc ttg tat tac cga gta atg
gaa tcc 1515Gln Arg Tyr Lys Leu Gly Val Arg Leu Tyr Tyr Arg Val Met
Glu Ser 445 450 455atg ctt aaa tca gaa gaa gaa cga tta tcc att caa
aat ttt agc aaa 1563Met Leu Lys Ser Glu Glu Glu Arg Leu Ser Ile Gln
Asn Phe Ser Lys460 465 470 475ctt ctg aat gac aac att ttt cat atg
tct tta ttg gcg tgc gct ctt 1611Leu Leu Asn Asp Asn Ile Phe His Met
Ser Leu Leu Ala Cys Ala Leu 480 485 490gag gtt gta atg gcc aca tat
agc aga agt aca tct cag aat ctt gat 1659Glu Val Val Met Ala Thr Tyr
Ser Arg Ser Thr Ser Gln Asn Leu Asp 495 500 505tct gga aca gat ttg
tct ttc cca tgg att ctg aat gtg ctt aat tta 1707Ser Gly Thr Asp Leu
Ser Phe Pro Trp Ile Leu Asn Val Leu Asn Leu 510 515 520aaa gcc ttt
gat ttt tac aaa gtg atc gaa agt ttt atc aaa gca gaa 1755Lys Ala Phe
Asp Phe Tyr Lys Val Ile Glu Ser Phe Ile Lys Ala Glu 525 530 535ggc
aac ttg aca aga gaa atg ata aaa cat tta gaa cga tgt gaa cat 1803Gly
Asn Leu Thr Arg Glu Met Ile Lys His Leu Glu Arg Cys Glu His540 545
550 555cga atc atg gaa tcc ctt gca tgg ctc tca gat tca cct tta ttt
gat 1851Arg Ile Met Glu Ser Leu Ala Trp Leu Ser Asp Ser Pro Leu Phe
Asp 560 565 570ctt att aaa caa tca aag gac cga gaa gga cca act gat
cac ctt gaa 1899Leu Ile Lys Gln Ser Lys Asp Arg Glu Gly Pro Thr Asp
His Leu Glu 575 580 585tct gct tgt cct ctt aat ctt cct ctc cag aat
aat cac act gca gca 1947Ser Ala Cys Pro Leu Asn Leu Pro Leu Gln Asn
Asn His Thr Ala Ala 590 595 600gat atg tat ctt tct cct gta aga tct
cca aag aaa aaa ggt tca act 1995Asp Met Tyr Leu Ser Pro Val Arg Ser
Pro Lys Lys Lys Gly Ser Thr 605 610 615acg cgt gta aat tct act gca
aat gca gag aca caa gca acc tca gcc 2043Thr Arg Val Asn Ser Thr Ala
Asn Ala Glu Thr Gln Ala Thr Ser Ala620 625 630 635ttc cag acc cag
aag cca ttg aaa tct acc tct ctt tca ctg ttt tat 2091Phe Gln Thr Gln
Lys Pro Leu Lys Ser Thr Ser Leu Ser Leu Phe Tyr 640 645 650aaa aaa
gtg tat cgg cta gcc tat ctc cgg cta aat aca ctt tgt gaa 2139Lys Lys
Val Tyr Arg Leu Ala Tyr Leu Arg Leu Asn Thr Leu Cys Glu 655 660
665cgc ctt ctg tct gag cac cca gaa tta gaa cat atc atc tgg acc ctt
2187Arg Leu Leu Ser Glu His Pro Glu Leu Glu His Ile Ile Trp Thr Leu
670 675 680ttc cag cac acc ctg cag aat gag tat gaa ctc atg aga gac
agg cat 2235Phe Gln His Thr Leu Gln Asn Glu Tyr Glu Leu Met Arg Asp
Arg His 685 690 695ttg gac caa att atg atg tgt tcc atg tat ggc ata
tgc aaa gtg aag 2283Leu Asp Gln Ile Met Met Cys Ser Met Tyr Gly Ile
Cys Lys Val Lys700 705
710 715aat ata gac ctt aaa ttc aaa atc att gta aca gca tac aag gat
ctt 2331Asn Ile Asp Leu Lys Phe Lys Ile Ile Val Thr Ala Tyr Lys Asp
Leu 720 725 730cct cat gct gtt cag gag aca ttc aaa cgt gtt ttg atc
aaa gaa gag 2379Pro His Ala Val Gln Glu Thr Phe Lys Arg Val Leu Ile
Lys Glu Glu 735 740 745gag tat gat tct att ata gta ttc tat aac tcg
gtc ttc atg cag aga 2427Glu Tyr Asp Ser Ile Ile Val Phe Tyr Asn Ser
Val Phe Met Gln Arg 750 755 760ctg aaa aca aat att ttg cag tat gct
tcc acc agg ccc cct acc ttg 2475Leu Lys Thr Asn Ile Leu Gln Tyr Ala
Ser Thr Arg Pro Pro Thr Leu 765 770 775tca cca ata cct cac att cct
cga agc cct tac aag ttt cct agt tca 2523Ser Pro Ile Pro His Ile Pro
Arg Ser Pro Tyr Lys Phe Pro Ser Ser780 785 790 795ccc tta cgg att
cct gga ggg aac atc tat att tca ccc ctg aag agt 2571Pro Leu Arg Ile
Pro Gly Gly Asn Ile Tyr Ile Ser Pro Leu Lys Ser 800 805 810cca tat
aaa att tca gaa ggt ctg cca aca cca aca aaa atg act cca 2619Pro Tyr
Lys Ile Ser Glu Gly Leu Pro Thr Pro Thr Lys Met Thr Pro 815 820
825aga tca aga atc tta gta tca att ggt gaa tca ttc ggg act tct gag
2667Arg Ser Arg Ile Leu Val Ser Ile Gly Glu Ser Phe Gly Thr Ser Glu
830 835 840aag ttc cag aaa ata aat cag atg gta tgt aac agc gac cgt
gtg ctc 2715Lys Phe Gln Lys Ile Asn Gln Met Val Cys Asn Ser Asp Arg
Val Leu 845 850 855aaa aga agt gct gaa gga agc aac cct cct aaa cca
ctg aaa aaa cta 2763Lys Arg Ser Ala Glu Gly Ser Asn Pro Pro Lys Pro
Leu Lys Lys Leu860 865 870 875cgc ttt gat att gaa gga tca gat gaa
gca gat gga agt aaa cat ctc 2811Arg Phe Asp Ile Glu Gly Ser Asp Glu
Ala Asp Gly Ser Lys His Leu 880 885 890cca gga gag tcc aaa ttt cag
cag aaa ctg gca gaa atg act tct act 2859Pro Gly Glu Ser Lys Phe Gln
Gln Lys Leu Ala Glu Met Thr Ser Thr 895 900 905cga aca cga atg caa
aag cag aaa atg aat gat agc atg gat acc tca 2907Arg Thr Arg Met Gln
Lys Gln Lys Met Asn Asp Ser Met Asp Thr Ser 910 915 920aac aag gaa
gag aaa tga ggatctcagg accttggtgg acactgtgta 2955Asn Lys Glu Glu
Lys 925cacctctgga ttcattgtct ctcacagatg tgactgtata actttcccag
gttctgttta 3015tggccacatt taatatcttc agctcttttt gtggatataa
aatgtgcaga tgcaattgtt 3075tgggtgagtc ctaagccact tgaaatgtta
gtcattgtta tttatacaag attgaaaatc 3135ttgtgtaaat cctgccattt
aaaaagttgt agcagattgt ttcctcttcc aaagtaaaat 3195tgctgtgctt
tatggatagt aagaatggcc ctagagtggg agtcctgata acccaggcct
3255gtctgactac tttgccttct tttgtagcat ataggtgatg tttgctcttg
tttttattaa 3315tttatatgta tattttttta atttaacatg aacaccctta
gaaaatgtgt cctatctatc 3375ttccaaatgc aatttgattg actgcccatt
caccaaaatt atcctgaact cttctgcaaa 3435aatggatatt attagaaatt
agaaaaaaat tactaatttt acacattaga ttttatttta 3495ctattggaat
ctgatatact gtgtgcttgt tttataaaat tttgctttta attaaataaa
3555agctggaagc aaagtataac catatgatac tatcatacta ctgaaacaga
tttcatacct 3615cagaatgtaa aagaacttac tgattatttt cttcatccaa
cttatgtttt taaatgagga 3675ttattgatag tactcttggt ttttatacca
ttcagatcac tgaatttata aagtacccat 3735ctagtacttg aaaaagtaaa
gtgttctgcc agatcttagg tatagaggac cctaacacag 3795tatatcccaa
gtgcactttc taatgtttct gggtcctgaa gaattaagat acaaattaat
3855tttactccat aaacagactg ttaattatag gagccttaat ttttttttca
tagagatttg 3915tctaattgca tctcaaaatt attctgccct ccttaatttg
ggaaggtttg tgttttctct 3975ggaatggtac atgtcttcca tgtatctttt
gaactggcaa ttgtctattt atcttttatt 4035tttttaagtc agtatggtct
aacactggca tgttcaaagc cacattattt ctagtccaaa 4095attacaagta
atcaagggtc attatgggtt aggcattaat gtttctatct gattttgtgc
4155aaaagcttca aattaaaaca gctgcattag aaaaagaggc gcttctcccc
tcccctacac 4215ctaaaggtgt atttaaacta tcttgtgtga ttaacttatt
tagagatgct gtaacttaaa 4275ataggggata tttaaggtag cttcagctag
cttttaggaa aatcactttg tctaactcag 4335aattattttt aaaaagaaat
ctggtcttgt tagaaaacaa aattttattt tgtgctcatt 4395taagtttcaa
acttactatt ttgacagtta ttttgataac aatgacacta gaaaacttga
4455ctccatttca tcattgtttc tgcatgaata tcatacaaat cagttagttt
ttaggtcaag 4515ggcttactat ttctgggtct tttgctacta agttcacatt
agaattagtg ccagaatttt 4575aggaacttca gagatcgtgt attgagattt
cttaaataat gcttcagata ttattgcttt 4635attgcttttt tgtattggtt
aaaactgtac atttaaaatt gctatgttac tattttctac 4695aattaatagt
ttgtctattt taaaataaat tagttgttaa gagtc 47404928PRTHomo
sapiensretinoblastoma 1 protein (RB1), retinoblastoma
susceptibility protein, OSRC. p105-Rb, pRb, RB 4Met Pro Pro Lys Thr
Pro Arg Lys Thr Ala Ala Thr Ala Ala Ala Ala1 5 10 15 Ala Ala Glu
Pro Pro Ala Pro Pro Pro Pro Pro Pro Pro Glu Glu Asp 20 25 30 Pro
Glu Gln Asp Ser Gly Pro Glu Asp Leu Pro Leu Val Arg Leu Glu 35 40
45 Phe Glu Glu Thr Glu Glu Pro Asp Phe Thr Ala Leu Cys Gln Lys Leu
50 55 60 Lys Ile Pro Asp His Val Arg Glu Arg Ala Trp Leu Thr Trp
Glu Lys65 70 75 80 Val Ser Ser Val Asp Gly Val Leu Gly Gly Tyr Ile
Gln Lys Lys Lys 85 90 95 Glu Leu Trp Gly Ile Cys Ile Phe Ile Ala
Arg Val Asp Leu Asp Glu 100 105 110 Met Ser Phe Thr Leu Leu Ser Tyr
Arg Lys Thr Tyr Glu Ile Ser Val 115 120 125 His Lys Phe Phe Asn Leu
Leu Lys Glu Ile Asp Thr Ser Thr Lys Val 130 135 140 Asp Asn Ala Met
Ser Arg Leu Leu Lys Lys Tyr Asp Val Leu Phe Ala145 150 155 160 Leu
Phe Ser Lys Leu Glu Arg Thr Cys Glu Leu Ile Tyr Leu Thr Gln 165 170
175 Pro Ser Ser Ser Ile Ser Thr Glu Ile Asn Ser Ala Leu Val Leu Lys
180 185 190 Val Ser Trp Ile Thr Phe Leu Leu Ala Lys Gly Glu Val Leu
Gln Met 195 200 205 Glu Asp Asp Leu Val Ile Ser Phe Gln Leu Met Leu
Cys Val Leu Asp 210 215 220 Tyr Phe Ile Lys Leu Ser Pro Pro Met Leu
Leu Lys Glu Pro Tyr Lys225 230 235 240 Thr Ala Val Ile Pro Ile Asn
Gly Ser Pro Arg Thr Pro Arg Arg Gly 245 250 255 Gln Asn Arg Ser Ala
Arg Ile Ala Lys Gln Leu Glu Asn Asp Thr Arg 260 265 270 Ile Ile Glu
Val Leu Cys Lys Glu His Glu Cys Asn Ile Asp Glu Val 275 280 285 Lys
Asn Val Tyr Phe Lys Asn Phe Ile Pro Phe Met Asn Ser Leu Gly 290 295
300 Leu Val Thr Ser Asn Gly Leu Pro Glu Val Glu Asn Leu Ser Lys
Arg305 310 315 320 Tyr Glu Glu Ile Tyr Leu Lys Asn Lys Asp Leu Asp
Arg Arg Leu Phe 325 330 335 Leu Asp His Asp Lys Thr Leu Gln Thr Asp
Ser Ile Asp Ser Phe Glu 340 345 350 Thr Gln Arg Thr Pro Arg Lys Ser
Asn Leu Asp Glu Glu Val Asn Ile 355 360 365 Ile Pro Pro His Thr Pro
Val Arg Thr Val Met Asn Thr Ile Gln Gln 370 375 380 Leu Met Met Ile
Leu Asn Ser Ala Ser Asp Gln Pro Ser Glu Asn Leu385 390 395 400 Ile
Ser Tyr Phe Asn Asn Cys Thr Val Asn Pro Lys Glu Ser Ile Leu 405 410
415 Lys Arg Val Lys Asp Ile Gly Tyr Ile Phe Lys Glu Lys Phe Ala Lys
420 425 430 Ala Val Gly Gln Gly Cys Val Glu Ile Gly Ser Gln Arg Tyr
Lys Leu 435 440 445 Gly Val Arg Leu Tyr Tyr Arg Val Met Glu Ser Met
Leu Lys Ser Glu 450 455 460 Glu Glu Arg Leu Ser Ile Gln Asn Phe Ser
Lys Leu Leu Asn Asp Asn465 470 475 480 Ile Phe His Met Ser Leu Leu
Ala Cys Ala Leu Glu Val Val Met Ala 485 490 495 Thr Tyr Ser Arg Ser
Thr Ser Gln Asn Leu Asp Ser Gly Thr Asp Leu 500 505 510 Ser Phe Pro
Trp Ile Leu Asn Val Leu Asn Leu Lys Ala Phe Asp Phe 515 520 525 Tyr
Lys Val Ile Glu Ser Phe Ile Lys Ala Glu Gly Asn Leu Thr Arg 530 535
540 Glu Met Ile Lys His Leu Glu Arg Cys Glu His Arg Ile Met Glu
Ser545 550 555 560 Leu Ala Trp Leu Ser Asp Ser Pro Leu Phe Asp Leu
Ile Lys Gln Ser 565 570 575 Lys Asp Arg Glu Gly Pro Thr Asp His Leu
Glu Ser Ala Cys Pro Leu 580 585 590 Asn Leu Pro Leu Gln Asn Asn His
Thr Ala Ala Asp Met Tyr Leu Ser 595 600 605 Pro Val Arg Ser Pro Lys
Lys Lys Gly Ser Thr Thr Arg Val Asn Ser 610 615 620 Thr Ala Asn Ala
Glu Thr Gln Ala Thr Ser Ala Phe Gln Thr Gln Lys625 630 635 640 Pro
Leu Lys Ser Thr Ser Leu Ser Leu Phe Tyr Lys Lys Val Tyr Arg 645 650
655 Leu Ala Tyr Leu Arg Leu Asn Thr Leu Cys Glu Arg Leu Leu Ser Glu
660 665 670 His Pro Glu Leu Glu His Ile Ile Trp Thr Leu Phe Gln His
Thr Leu 675 680 685 Gln Asn Glu Tyr Glu Leu Met Arg Asp Arg His Leu
Asp Gln Ile Met 690 695 700 Met Cys Ser Met Tyr Gly Ile Cys Lys Val
Lys Asn Ile Asp Leu Lys705 710 715 720 Phe Lys Ile Ile Val Thr Ala
Tyr Lys Asp Leu Pro His Ala Val Gln 725 730 735 Glu Thr Phe Lys Arg
Val Leu Ile Lys Glu Glu Glu Tyr Asp Ser Ile 740 745 750 Ile Val Phe
Tyr Asn Ser Val Phe Met Gln Arg Leu Lys Thr Asn Ile 755 760 765 Leu
Gln Tyr Ala Ser Thr Arg Pro Pro Thr Leu Ser Pro Ile Pro His 770 775
780 Ile Pro Arg Ser Pro Tyr Lys Phe Pro Ser Ser Pro Leu Arg Ile
Pro785 790 795 800 Gly Gly Asn Ile Tyr Ile Ser Pro Leu Lys Ser Pro
Tyr Lys Ile Ser 805 810 815 Glu Gly Leu Pro Thr Pro Thr Lys Met Thr
Pro Arg Ser Arg Ile Leu 820 825 830 Val Ser Ile Gly Glu Ser Phe Gly
Thr Ser Glu Lys Phe Gln Lys Ile 835 840 845 Asn Gln Met Val Cys Asn
Ser Asp Arg Val Leu Lys Arg Ser Ala Glu 850 855 860 Gly Ser Asn Pro
Pro Lys Pro Leu Lys Lys Leu Arg Phe Asp Ile Glu865 870 875 880 Gly
Ser Asp Glu Ala Asp Gly Ser Lys His Leu Pro Gly Glu Ser Lys 885 890
895 Phe Gln Gln Lys Leu Ala Glu Met Thr Ser Thr Arg Thr Arg Met Gln
900 905 910 Lys Gln Lys Met Asn Asp Ser Met Asp Thr Ser Asn Lys Glu
Glu Lys 915 920 925 539DNAArtificial Sequencesynthetic PCR primer
used for wild-type plasmids 5aagcttgcgg ccgcgatgga gccgctgaag
gtggaaaag 39636DNAArtificial Sequencesynthetic PCR primer used for
wild-type plasmids 6ggtacctcta gattaggatg ctctgatgtt ggcgtc
36732DNAArtificial Sequencesynthetic PCR primer used for
FLAG-SMYD3-deltaN44 mutant plasmid 7ggggtacctt aggatgctct
gatgttggcg tc 32839DNAArtificial Sequencesynthetic PCR primer used
for FLAG-SMYD3-deltaN44 mutant plasmid 8cggaattctg gcgcgatgga
gccgctgaag gtggaaaag 39932DNAArtificial Sequencesynthetic PCR
primer used for FLAG-SMYD3-deltaN99 mutant plasmid 9cggaattctg
actccgttcg acttcttggc ag 321036DNAArtificial Sequencesynthetic PCR
primer used for FLAG-SMYD3-deltaN244 mutant plasmid 10cggaattctc
ggaagcagct gagggaccag tactgc 361134DNAArtificial Sequencesynthetic
PCR primer used for FLAG-SMYD3-deltaN34 mutant plasmid 11cggaattcac
ccttggcgta cacggtgtgc aagg 34127PRTArtificial Sequencesynthetic
conserved Suppressor of variegation 3-9 (Su 3-9),
Enhancer-of-zeste, Trithorax (SET) domain 12Asn His Ser Cys Xaa Xaa
Asn1 5 138PRTArtificial Sequencesynthetic conserved Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) domain
13Gly Glu Glu Leu Xaa Xaa Xaa Tyr1 5 146PRTArtificial
Sequencesynthetic 6xHis peptide 14His His His His His His1 5
1523PRTArtificial Sequencesynthetic Suppressor of variegation 3-9
(Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N domain from
histone methyltransferase SMYD3 15Lys Val Glu Lys Phe Ala Thr Ala
Asn Arg Gly Asn Gly Leu Arg Ala1 5 10 15 Val Thr Pro Leu Arg Pro
Gly 20 1623PRTArtificial Sequencesynthetic Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N
domain from histone methyltransferase DIM-5_Nc 16Pro Leu Gln Ile
Phe Arg Thr Lys Asp Arg Gly Trp Gly Val Lys Cys1 5 10 15 Pro Val
Asn Ile Lys Arg Gly 20 1725PRTArtificial Sequencesynthetic
Suppressor of variegation 3-9 (Su 3-9), Enhancer-of-zeste,
Trithorax (SET) SET-N domain from histone methyltransferase
SET7/9_Hs 17Arg Val Tyr Val Ala Glu Ser Leu Ile Ser Ser Ala Gly Glu
Gly Leu1 5 10 15 Phe Ser Lys Val Ala Val Gly Pro Asn 20 25
1823PRTArtificial Sequencesynthetic Suppressor of variegation 3-9
(Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N domain from
histone methyltransferase Cir4_Sp 18Pro Leu Glu Ile Phe Lys Thr Lys
Glu Lys Gly Trp Gly Val Arg Ser1 5 10 15 Leu Arg Phe Ala Pro Ala
Gly 20 1923PRTArtificial Sequencesynthetic Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N
domain from histone methyltransferase SET1_Sc 19Pro Val Met Phe Ala
Arg Ser Ala Ile His Asn Trp Gly Leu Tyr Ala1 5 10 15 Leu Asp Ser
Ile Ala Ala Lys 20 2023PRTArtificial Sequencesynthetic Suppressor
of variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET)
SET-N domain from histone methyltransferase SET2_Sc 20Pro Ile Ala
Ile Phe Lys Thr Lys His Lys Gly Tyr Gly Val Arg Ala1 5 10 15 Glu
Gln Asp Ile Glu Ala Asn 20 2123PRTArtificial Sequencesynthetic
Suppressor of variegation 3-9 (Su 3-9), Enhancer-of-zeste,
Trithorax (SET) SET-N domain from histone methyltransferase G9a_Hs
21Arg Leu Gln Leu Tyr Arg Thr Ala Lys Met Gly Trp Gly Val Arg Ala1
5 10 15 Leu Gln Thr Ile Pro Gln Gly 20 2224PRTArtificial
Sequencesynthetic Suppressor of variegation 3-9 (Su 3-9),
Enhancer-of-zeste, Trithorax (SET) SET-N domain from histone
methyltransferase SUV39H1_Hs 22Asp Leu Cys Ile Phe Arg Thr Asp Asp
Gly Arg Gly Trp Gly Val Arg1 5 10 15 Thr Leu Glu Lys Ile Arg Lys
Asn 20 2323PRTArtificial Sequencesynthetic Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N
domain from histone methyltransferase PR-SET7_At 23Gly Met Lys Ile
Asp Leu Ile Asp Gly Lys Gly Arg Gly Val Ile Ala1 5 10 15 Thr Lys
Gln Phe Ser Arg Gly 20 2424PRTArtificial Sequencesynthetic
Suppressor of variegation 3-9 (Su 3-9), Enhancer-of-zeste,
Trithorax (SET) SET-N domain from histone methyltransferase EZH2_Hs
24Lys His Leu Leu Leu Ala Pro Ser Asp Val Ala Gly Trp Gly Ile Phe1
5 10 15 Ile Lys Asp Pro Val Gln Lys Asn 20 2523PRTArtificial
Sequencesynthetic Suppressor of variegation 3-9 (Su 3-9),
Enhancer-of-zeste, Trithorax (SET) SET-N domain from histone
methyltransferase KRP_At 25Asn Leu Glu Val Phe Arg Ser Ala Lys Lys
Gly Trp Ala Val Arg Ser1 5 10 15 Trp Glu Tyr Ile Pro Ala Gly 20
2623PRTArtificial Sequencesynthetic Suppressor of variegation 3-9
(Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N domain from
histone methyltransferase ASH1_Dm 26Gly Val Glu Arg Phe Met Thr Ala
Asp Lys Gly Trp Gly Val Arg Thr1 5 10 15 Lys Leu Pro Ile Ala Lys
Gly
20 2723PRTArtificial Sequencesynthetic Suppressor of variegation
3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N domain from
histone methyltransferase SETDB1_Hs 27Arg Leu Gln Leu Phe Lys Thr
Gln Asn Lys Gly Trp Gly Ile Arg Cys1 5 10 15 Leu Asp Asp Ile Ala
Lys Gly 20 2823PRTArtificial Sequencesynthetic Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N
domain from histone methyltransferase MLL2_Hs 28Ala Val Gly Val Tyr
Arg Ser Ala Ile His Gly Arg Gly Leu Phe Cys1 5 10 15 Lys Arg Asn
Ile Asp Ala Gly 20 2910PRTArtificial Sequencesynthetic wild type
(Wt) retinoblatoma 1 (RB1) conserved C-terminal substrate domain
peptide 29Pro Thr Pro Thr Lys Met Thr Pro Arg Ser1 5 10
3016PRTArtificial Sequencesynthetic wild type (Wt) retinoblatoma 1
(RB1) conserved C-terminal substrate domain peptide 30Glu Ala Asp
Gly Ser Lys His Leu Pro Gly Glu Ser Lys Phe Gln Gln1 5 10 15
3110PRTArtificial Sequencesynthetic K824A retinoblatoma 1 (RB1)
C-terminal substrate domain peptide 31Pro Thr Pro Thr Ala Met Thr
Pro Arg Ser1 5 10 3216PRTArtificial Sequencesynthetic K889A mutated
retinoblatoma 1 (RB1) C-terminal substrate domain peptide 32Glu Ala
Asp Gly Ser Ala His Leu Pro Gly Glu Ser Lys Phe Gln Gln1 5 10 15
3316PRTArtificial Sequencesynthetic K896A mutated retinoblatoma 1
(RB1) C-terminal substrate domain peptide 33Glu Ala Asp Gly Ser Lys
His Leu Pro Gly Glu Ser Ala Phe Gln Gln1 5 10 15 3434PRTArtificial
Sequencesynthetic SMYD3-wt wild type conserved Suppressor of
variegation 3-9 (Su 3-9), Enhancer-of-zeste, Trithorax (SET) SET-N
region 34Met Glu Pro Leu Lys Val Glu Lys Phe Ala Thr Ala Asn Arg
Gly Asn1 5 10 15 Gly Leu Arg Ala Val Thr Pro Leu Arg Pro Gly Glu
Leu Leu Phe Arg 20 25 30 Ser Asp3534PRTArtificial Sequencesynthetic
SMYD3-SETNm1 mutated Suppressor of variegation 3-9 (Su 3-9),
Enhancer-of-zeste, Trithorax (SET) SET-N region 35Met Glu Pro Leu
Lys Val Glu Lys Phe Ala Thr Ala Asn Arg Ala Asn1 5 10 15 Ala Leu
Arg Ala Val Thr Pro Leu Arg Pro Gly Glu Leu Leu Phe Arg 20 25 30
Ser Asp3634PRTArtificial Sequencesynthetic SMYD3-SETNm2 mutated
Suppressor of variegation 3-9 (Su 3-9), Enhancer-of-zeste,
Trithorax (SET) SET-N region 36Met Glu Pro Leu Lys Val Glu Lys Phe
Ala Thr Ala Asn Arg Ala Asn1 5 10 15 Gly Leu Arg Ala Val Thr Pro
Leu Arg Pro Gly Glu Leu Leu Phe Arg 20 25 30 Ser
Asp3734PRTArtificial Sequencesynthetic SMYD3-SETNm3 mutated
Suppressor of variegation 3-9 (Su 3-9), Enhancer-of-zeste,
Trithorax (SET) SET-N region 37Met Glu Pro Leu Lys Val Glu Lys Phe
Ala Thr Ala Asn Arg Gly Asn1 5 10 15 Gly Leu Arg Ala Val Thr Pro
Leu Arg Pro Ala Glu Leu Leu Phe Arg 20 25 30 Ser
Asp3810PRTArtificial Sequencesynthetic 10xHis peptide 38His His His
His His His His His His His1 5 10
* * * * *