U.S. patent application number 11/846555 was filed with the patent office on 2008-02-14 for nucleotide analogs with six-membered rings.
Invention is credited to Frank Bergmann, Horst Donner, Dieter Heindl, Piet Herdewijn, Herbert Von Der Eltz.
Application Number | 20080038745 11/846555 |
Document ID | / |
Family ID | 33040929 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080038745 |
Kind Code |
A1 |
Bergmann; Frank ; et
al. |
February 14, 2008 |
NUCLEOTIDE ANALOGS WITH SIX-MEMBERED RINGS
Abstract
The present invention is related to compounds comprising
six-membered rings capable of being incorporated into nucleic
acids. Particularly, the six-membered ring is a derivative of
cyclohexane, cyclohexene, tetrahydropyran, tetrahydrothiopyran or
piperidine. These compounds may be used to build up oligomeric
compounds. The invention is further related to uses of these
oligomeric compounds for hybridization and as probes. In addition,
methods for the detection of nucleic acids are provided wherein the
oligomeric compounds are used.
Inventors: |
Bergmann; Frank; (Iffeldorf,
DE) ; Donner; Horst; (Muenchen, DE) ; Von Der
Eltz; Herbert; (Weilheim, DE) ; Heindl; Dieter;
(Paehl, DE) ; Herdewijn; Piet; (Wezemaal,
BE) |
Correspondence
Address: |
Marilyn L. Amick;Roche Diagnostics Operations, Inc.
9115 Hauge Road, Bldg. D
Indianapolis
IN
46250
US
|
Family ID: |
33040929 |
Appl. No.: |
11/846555 |
Filed: |
August 29, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10816298 |
Apr 1, 2004 |
7276592 |
|
|
11846555 |
Aug 29, 2007 |
|
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|
Current U.S.
Class: |
435/6.12 ;
435/6.1; 536/23.1; 536/26.1; 536/26.21; 536/26.6 |
Current CPC
Class: |
C07H 19/10 20130101;
C07H 21/04 20130101; Y02P 20/55 20151101; G01N 33/58 20130101; C07H
21/00 20130101; C07D 405/04 20130101; G01N 33/53 20130101; A61K
31/675 20130101; A61K 31/513 20130101; C12P 19/38 20130101; C07H
19/06 20130101; C12P 19/34 20130101; C12Q 1/68 20130101; C07H 19/16
20130101; G01N 37/00 20130101; C07D 495/04 20130101; A61K 31/52
20130101; G01N 33/566 20130101 |
Class at
Publication: |
435/006 ;
536/023.1; 536/026.1; 536/026.21; 536/026.6 |
International
Class: |
C12Q 1/68 20060101
C12Q001/68; C07H 19/00 20060101 C07H019/00; C07H 21/02 20060101
C07H021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2003 |
EP |
EP 03007844.8 |
Claims
1. An oligomeric compound comprising a monomeric unit having a
structure of the formula S-B-L-R.sup.7 wherein S is a moiety
comprising a six-membered ring, B is a heterocyclic base, L is a
linking moiety, and R.sup.7 is selected from the group consisting
of a label, a protecting group or a solid phase.
2. The compound according to claim 1 wherein the six-membered ring
is a derivative selected from the group consisting of cyclohexane,
cyclohexene, tetrahydropyran, tetrahydrothiopyran or
piperidine.
3. An oligomeric compound comprising a monomer having a structure
of the formula ##STR4## wherein L is a linking moiety covalently
and B is a heterocyclic base, R.sup.7 is selected from the group
consisting of protecting group, a label, and a solid phase; R.sup.8
is selected from the group consisting of --H and --OR.sup.11;
R.sup.9 and R.sup.11 selected from the group consisting of --H, a
linking moiety covalently coupled to a solid phase, a phosphate, a
phosphodiester with a nucleotide, a modified nucleotide, an
oligonucleotide, and a modified oligonucleotide; R.sup.10 is
selected from the group consisting of --H, --OH, alkyl, halogen,
--O--R.sup.5, --S--R.sup.5, NR.sup.5R.sup.5a, a label, and a
linking moiety covalently coupled to a solid phase. Y is selected
from the group consisting of O, S, NR.sup.5, CR.sup.5aR.sup.5b, and
CR.sup.5a, and the bond between the C-1 atom of the six-membered
ring and Y is a single bond when Y is O, S, NR.sup.5, or
CR.sup.5aR.sup.5b and a double bond when Y is CR.sup.5a; and
R.sup.5 is selected from the group consisting of alkyl, alkenyl,
alkinyl, aryl, acyl, a protecting group, and --H and R.sup.5a and
R.sup.5b are selected from the group consisting of alkyl, alkenyl,
alkinyl, aryl, acyl, and --H.
4. The compound according to claim 3 wherein the heterocyclic base
is selected from the group consisting of adenine, guanine,
cytosine, thymine, uracil, and methyl-cytosine.
5. The compound according to claim 3 wherein the linking moiety L
comprises carbon, oxygen or nitrogen atoms and a reactive
group.
6. The compound according to claim 3 wherein R.sup.7 is a label
selected from the group consisting of a dye and a hapten.
7. The compound according to claim 6 wherein the dye is selected
from the group consisting of a fluorescein dye, a rhodamine dye, a
cyanine dye, a coumarin dye, and an azo dye.
8. The compound according to claim 6 wherein the hapten is
biotin.
9. The compound according to claim 3 wherein R.sup.8 is
--OR.sup.11, R.sup.9 and R.sup.11 are an oligonucleotide or a
modified oligonucleotide, and R.sup.10 is --H or --OH.
10. The compound according to claim 3 wherein Y is selected from
the group consisting of O, S, and CR.sup.52R.sup.5b.
11. The compound according to claim 3 wherein Y is CR.sup.5a and
R.sup.5b is selected from the group consisting of alkyl, alkenyl,
alkinyl, aryl, acyl, and --H.
12. A composition for analyzing interactions between target nucleic
acids and oligomeric compounds comprising an array of a plurality
of oligomeric compounds having different sequences wherein the
oligomeric compound is an oligomeric compound according to claim 3
wherein a solid phase is covalently coupled to a member selected
from the group consisting of R.sup.7, R.sup.9, R.sup.10, and
R.sup.11.
13. A method for determining the presence or amount of a target
nucleic acid in a sample comprising the steps of: providing a
sample suspected of containing the target nucleic acid, providing a
compound according to claim 1 or 3, wherein said compound is
essentially complementary to a part or all of the target nucleic
acid, optionally amplifying the target nucleic acid with a
template-dependent DNA polymerase and primers, contacting the
sample with the compound under conditions for binding the compound
to the target nucleic acid, determining the binding product or the
degree of hybridization between the target nucleic acid and the
compound as a measure of the presence, absence or amount of the
target nucleic acid.
14. The method according to claim 13 whereby the degree of
hybridization is determined by the quantity of the first or second
fluorescent label that is released from the oligomeric compound
hybridized to the target nucleic acid by exnuclease hydrolysis by
the template-dependent DNA polymerase.
15. The method according to claim 14 further comprising the steps
of: performing a cycling step comprising an amplifying step and a
hybridizing step, wherein the amplifying step comprises contacting
the sample with primers to produce a an amplification product if
target nucleic acid is present in said sample, wherein the
hybridizing step comprises contacting the sample with a pair of
probes, wherein at least one of the probes is an oligomeric
compound comprising a monomeric unit comprising a six-membered
ring, wherein the members of the pair of probes hybridize to the
amplification product within no more than five nucleotides of each
other, wherein the first probe of the pair of probes is labeled
with a donor fluorescent label and wherein a second probe of the
pair of probes is labeled with a corresponding acceptor fluorescent
label, and detecting the presence or absence of fluorescence
resonance energy transfer between the donor fluorescent label of
the first probe and the acceptor fluorescent label of the second
probe, wherein the presence of fluorescence resonance energy
transfer is indicative of the presence of the target nucleic acid
in the sample, and wherein the absence of fluorescence resonance
energy transfer is indicative of the absence of the target nucleic
acid in the sample.
16. A method for determining the presence or amount of a target
nucleic acid in a sample comprising the steps of: providing a
target nucleic acid from a sample to be analyzed; synthesizing
double stranded complementary DNA from the target nucleic acid,
amplifying the target nucleic acid in the presence of a compound
according to claim 1 and nucleoside triphosphates whereby a
labelled nucleic acid is obtained, hybridizing the labelled target
nucleic acid to an array of oligomeric compounds at a defined
location, and measuring the fluorescence intensities at each
defined location whereby the presence or the amount of the target
nucleic acid is determined.
17. A kit for determining a target nucleic acid in a sample
comprising a template-dependent polymerase, a set of primers,
nucleotides, and an oligomeric compound according to claim 1,
wherein R.sup.7 is a label.
18. A kit for determining a target nucleic acid in a sample
comprising a template-dependent polymerase, a set of primers,
nucleotides, and an oligomeric compound according to claim 3,
wherein R.sup.7 is a label.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No. 10/816,298
filed Apr. 1, 2004 and claims priority to EP 03007844.8 filed Apr.
5, 2003.
FIELD OF THE INVENTION
[0002] The present invention is related to compounds comprising
six-membered rings capable of being incorporated into nucleic
acids. Particularly, the six-membered ring is a derivative of
cyclohexane, cyclohexene, tetrahydropyran, tetrahydrothiopyran or
piperidine. These compounds may be used to build up oligomeric
compounds. The invention is further related to uses of these
oligomeric compounds for hybridization and as probes. In addition,
methods for the detection of nucleic acids are provided wherein the
oligomeric compounds are used.
BACKGROUND OF THE INVENTION
[0003] In the field of molecular diagnostics, the detection of
target nucleic acids with the polymerase chain reaction (PCR) plays
an important role. The routine screening of blood banks for the
presence of Human Immunodeficiency Virus (HIV), Hepatitis-B (HBV)
or C Virus (HCV) is an example of the large-scale application of
PCR-based diagnostics. Automated systems for PCR-based analysis
often make use of real-time detection of product amplification
during the PCR process. Key to such methods is the use of modified
oligonucleotides carrying reporter groups or labels.
[0004] In its simplest form, PCR is an in vitro method for the
enzymatic synthesis of specific nucleic acid sequences, using two
oligonucleotide primers that hybridize to opposite strands and
flank the target sequence that is the region of interest in the
target nucleic acid. A repetitive series of reaction steps
involving template denaturation, primer annealing, and the
extension of the annealed primers by DNA polymerase
(DNA:deoxyribonucleic acid) results in the exponential accumulation
of a specific fragment whose termini are defined by the 5' ends of
the primers.
[0005] The detection of DNA amplification products generated by a
PCR process can, on the one hand, be accomplished in separate
working steps. These may involve the characterization of amplified
fragments with respect to their electrophoretic mobility and/or the
analysis of denatured amplification products attached to a solid
support using a hybridization probe.
[0006] On the other had the detection of DNA amplification products
can be done in a so-called "homogeneous" assay system. A
"homogeneous" assay system comprises reporter molecules or labels
which generate a signal while the target sequence is amplified. An
example for a "homogeneous" assay system is the TaqMan.RTM. system
that has been detailed in U.S. Pat. No. 5,210,015, U.S. Pat. No.
5,804,375and U.S. Pat. No. 5,487,972. Briefly, the method is based
on a double-labeled probe and the 5'-3' exonuclease activity of Taq
DNA polymerase. The probe is complementary to the target sequence
to be amplified by the PCR process and is located between the two
PCR primers during each polymerization cycle step. The probe has
two fluorescent labels attached to it. One is a reporter dye, such
as 6-carboxyfluorescein FAM), which has its emission spectra
quenched by energy transfer due to the spatial proximity of a
second fluorescent dye, 6-carboxy-tetramethyl-rhodamine (TAMRA). In
the course of each amplification cycle, the Taq DNA polymerase in
the process of elongating a primed DNA strand displaces and
degrades the annealed probe, the latter due to the intrinsic 5'-3'
exonuclease activity of the polymerase. The mechanism also frees
the reporter dye from quenching activity of TAMRA. As a
consequence, the fluorescent activity increases with an increase in
cleavage of the probe, which is proportional to the amount of PCR
product formed. Accordingly, amplified target sequence is measured
detecting the intensity of released fluorescence label.
[0007] A similar principle of energy transfer between fluorescent
dye molecules applies to "homogeneous" assays using so-called
"molecular beacons" (U.S. Pat. No. 6,103,476). These are
hairpin-shaped nucleic acid molecules with an internally quenched
fluorophore whose fluorescence is restored when they bind to a
target nucleic acid (U.S. Pat. No. 6,103,476). They are designed in
such a way that the loop portion of the molecule is a probe
sequence complementary to a region within the target sequence of
the PCR process. The stem is formed by the annealing of
complementary arm sequences on the ends of the probe sequence. A
fluorescent moiety is attached to the end of one arm and a
quenching moiety is attached to the end of the other arm. The stem
keeps these two moieties in close proximity to each other, causing
the fluorescence of the fluorophore to be quenched by energy
transfer. Since the quencher moiety is a non-fluorescent
chromophore and emits the energy that it receives from the
fluorophore as heat, the probe is unable to fluoresce. When the
probe encounters a target molecule, it forms a hybrid that is
longer and more stable than the stem hybrid and its rigidity and
length preclude the simultaneous existence of the stem hybrid.
Thus, the molecular beacon undergoes a spontaneous conformational
reorganization that forces the stem apart, and causes the
fluorophore and the quencher to move away from each other, leading
to the restoration of fluorescence which can be detected.
[0008] More examples for "homogeneous" assay systems are provided
by the formats used in the LightCycler.RTM. instrument (see e.g.
U.S. Pat. No. 6,174,670), some of them sometimes called "kissing
probe" formats. Again, the principle is based on two interacting
dyes which, however, are characterized in that the donor-dye
excites an acceptor-dye by fluorescence resonance energy transfer.
An exemplified method uses two modified oligonucleotides as
hybridization probes, which hybridize to adjacent internal
sequences of the target sequence of the PCR process. The 5'-located
modified oligonucleotide has a donor-dye as a label at its 3' end.
The 3'-located modified oligonucleotide has an acceptor-dye at its
5' end. Following the head-to-tail oriented annealing of the two
modified oligonucleotides to the target sequence in the course of
an amplification cycle, donor and acceptor dyes are brought in
close proximity. Upon specific excitation of the donor dye by means
of a monochromatic light pulse, acceptor dye fluorescence is
detected providing a measure for the amount of PCR product
formed.
[0009] Another assay format in the so-called "array" format. An
"array" is an arrangement of addressable locations on a device (see
e.g. U.S. Pat. No. 5,143,854, U.S. Pat. No. 6,022,963, U.S. Pat.
No. 6,156,501, WO 90/15070, WO 92/10092). The number of locations
can range from several to at least hundreds of thousands. Most
importantly, each location represents a totally independent
reaction site. Each location carries a nucleic acid as e.g. an
"oligomeric compound", which can serve as a binding partner for a
second nucleic acid, in particular a target nucleic acid. Methods
for the manufacturing thereof are described in EP-A-0 476 014 and
Hoheisal, J. D., TIBTECH (1997), Vol. 15, 465-469, WO 89/10977, WO
89/11548, U.S. Pat. No. 5,202,231, U.S. Pat. No. 5,002,867, WO
93/17126). Further development has provided methods for making very
large arrays of oligonucleotide probes in very small areas. (U.S.
Pat. No. 5,143,854, WO 90/15070, WO 92/10092). Microfabricated
arrays of large numbers of oligonucleotide probes, called "DNA
chips" offer great promise for a wide variety of applications (see
e.g. U.S. Pat. No. 6,156,501 and U.S. Pat. No. 6,022,963). The
basic steps of the method are that nucleic acid from control and
treatment samples is isolated and labeled with different
fluorescent dyes incorporated during an amplification process. In
more detail, this is performed according to the method described in
U.S. Pat. No. 5,545,522; U.S. Pat. No. 5,716,785; U.S. Pat. No.
5,891,636; U.S. Pat. No. 6,192,170 whereby double stranded cDNA is
synthesized with a primer comprising the bacterial T7-Promoter and
labeled RNA is transcribed in the presence of ribonucleoside
triphosphates whereby labels are attached to some of the nucleoside
triphosphates. These labeled nucleic acids are then optionally
fragmented, mixed and hybridized to the arrayed oligomeric
compounds. An optical device is then used to measure the relative
intensities of each dye for each individual spot. The ratio of
fluorescence levels between the two probes indicates the relative
gene expression between the samples. By these processes researchers
can evaluate an entire set of genes simultaneously rather than
looking at the effects of single genes one at a time. High
differential expression of specific genes can then be followed up
by conventional means such as northern blot or quantitative RT-PCR.
Data from multiple experiments can be combined in order to assign
functional information to genes of otherwise unknown function.
Genes showing similar expression profiles across differing states
are likely to participate in common physiological or metabolic
pathways.
[0010] Cluster analysis programs have been developed which allow
detection of co-expressed groups of genes reflecting information on
function.
[0011] The oligomeric compound or modified oligonucleotide used in
"homogeneous" assay systems comprises nucleotides, modified
nucleotides or non-nucleotide compounds, i.e. the monomeric units,
to which labels such as dyes as reporter molecules are attached.
The features of such monomeric units are that they can be attached
to and/or integrated into the sugar-phosphate polymer backbone of a
nucleic acid, they do not prevent the pairing of the modified
oligonucleotide with its complementary target sequence, and they
provide functional groups for the attachment of one or more
labels.
[0012] These requirements can be fulfilled by nucleotides, modified
nucleotides or non-nucleotide compounds. In addition, the
TaqMan.RTM. format requires that the oligomeric compound can be
digested by 5'-3' exonuclease activity of a template-dependent
DNA-polymerase. Various modified nucleotides have also been
incorporated into oligomeric compounds to influence their
hybridization behavior or stability, see e.g. WO02/12263.
[0013] Several compounds and their use for incorporation as
monomeric units into nucleic acids are known in the art. Such
compounds provide functional groups and/or linking moieties for the
covalent attachment of reporter groups or labels. In the course of
the chemical synthesis of the oligomeric compounds, the skeletal
structure of the "non-nucleotide compound" or "modified nucleotide"
is connected with the "oligonucleotide" backbone, for example by
phosphoramidite-based chemistry resulting in a phosphodiester. A
given incorporated compound thus represents a "modified nucleotide"
or "non-nucleotide compound" within the newly generated "modified
nucleotide". A label is bound by a reactive group of a linking
moiety, exemplified by but not limited to an amino function that is
present on the skeletal structure or on the "linking moiety", which
connects the skeleton with the reactive group. A label can be
covalently attached to the compound prior to the synthesis of a
"modified oligonucleotide" or afterwards, upon the removal of an
optional protecting group from the functional group to which the
label is to be coupled. Various "modified nucleotides" have also
been incorporated into oligomeric compounds to influence their
hybridization behavior or stability, see e.g. WO02/12263.
[0014] Several references disclose modified nucleotides comprising
six-membered rings and their incorporation into oligonucleotides.
WO93/25565 discloses 1,5 anhydrobexitol nucleoside analogs and
pharmaceutical uses thereof. Further 1,5 anhydrobexitol or hexitol
nucleoside analogues are disclosed in Verheggen, I., et al.
Nucleosides & Nucleotides 15 (1996) 325-335; Verheggen et al.,
J. of Med. Chem. 36 (1993) 2033-2040; Perez-Perez, M.-J., et al.,
Bioorg. & Med. Chem. Letters 6 (1996) 1457-1460; Vastmans, K.,
et al., Collect. Symp. Series 2 (1999) 156-160; Andersen, M. W. et
al., Pergamon, Tetrahedron Lett. 37 (1996) 8147-8150; Ostrowski,
T., et al., J. Med. Chem, 41 (1998) 4343-4353; Allart, B., et al.,
Tetrahedron 55 (1999) 6527-6546; De Bouvere, B., et al., Liebigs
Ann./Recueil (1997) 1453-1461; Verheggen, I., J. Med. Chem. 38
(1995) 826-835. Antiviral tetrahydropyrans are disclosed in U.S.
Pat. No. 5,314,893. A deoxyadenosine bisphosphate derivative
containing a six-membered ring is described by Brown, S. G., Drug
Development Research 49 (2000) 253-259.
[0015] WO 01/18003 describes six-membered at least partially
unsaturated carboxylic nucleoside compounds. Pharmaceutical uses
are primarily considered. Further cyclohexane or cyclohexene
containing nucleoside analogs are disclosed in Wang, J., et al., J.
Med. Chem. 43 (2000) 736-745; Rosenquist A., et al., J. Org. Chem.
61 (1996) 6282-6288; Ramesh, K., et al., J. Org. Chem. 57 (1992)
5861-5868, Perez-Perez, M. J., et al., J. Org. Chem. 60 (1995)
1531-1537; Konkel, M. J., and Vince, R., Tetrahedron 52 (1996)
799-808; Arango, J. H., Nucleosides & Nucleotides 12 (1993)
773-784; Konkel M. J., and Vince, R., Nucleosides & Nucleotides
14 (1995) 2061-2077; Katagiri, N., et al., Nucleosides &
Nucleotides 15 (1996) 631-647; Luyten, I., and Herdewijn, P.,
Tetrahedron 52 (1996) 9249-9262; Wang, J., et al., J. Med. Chem. 43
(2000) 736-745; Wang, J., and Herdewijn, P., J. Org. Chem. 64
(1999) 7820-7827; Maurinsh, Y., et al., J. Org. Chem. 62 (1997)
2861-2871; Wang, J., et al., Nucleosides Nucleotides Nucleic Acids
20 (2001) 785-788; Maurinsh, Y., et al., Chem. Eur. J. 5 (1999)
2139-2150.
[0016] WO 96/05213 discloses oligomers consisting or comprising 1,5
anhydrobexitol nucleoside analogues and their uses. WO97/30064
relates to oligomers comprising or containing 1,5 anhydrobexitol
nucleoside analogs which exhibit sequence specific binding to
complementary sequences. Further, the synthesis thereof is
disclosed and their use in diagnosis, hybridization, isolation of
nucleic acids, site-specific DNA modification and therapeutics.
Further hexitol or 1,5 anhydrobexitol containing nucleic acids are
disclosed in Vastmans, K., et al., Biochem. 39 (2000) 12757-12765;
Pochet, S., et al., Nucleosides & Nucleotides 18 (1999)
1015-1017, Kozlov., I. A., et al., Chemistry 6 (2000) 151-155;
Vandermeeren, M., et al., Biochem. Pharm. 59 (2000) 655-663;
Hendrix, C., et al., Chem. Eur. J. 3 (1997) 1513-1520; Allart, B.,
et al., Chem. Eur. J. 8 (1999) 2424-2431; Kozlov, I. A., et al., J.
Am. Chem. Soc. 121 (1999) 2653-2656; Hendrix, C., et al., Chem.
Eur. J. 3 (1997) 110-120; Van Aerschot, A., et al., Angew. Chem.
Int. Ed. Engl. 34 (1995) 1338-1339, Froeyen, M., et al., Helvetica
Chimica. Acta 83 (2000) 2153-2182; Boudou, V., et al., Nucleic
Acids Research 27 (1999) 1450-1456; Lescrinier, E., et al., Chem.
Biol. 7 (2000) 719-731; Kozlov, I. A., et al., J. Am. Chem. Soc.
121 (1999) 1108-1109; Herdewijn, P., et al., Nucl. Acids Symp.
Series 31 (1994) 161-162; Lescrinier, E., et al., Helvetica Chimica
Acta 83 (2000) 1291-1310; Kozlov, I. A., et al., J. Am. Chem. Soc.
121 (1999) 5856-5859; De Winter, H., et al., J. Am. Chem. Soc. 120
(1998) 5381-5394; Atkins, D., et al., Pharmazie 55 (2000) 615-617.
Pyranosyl oligomers are also disclosed in WO 98/25943 and WO
99/15509.
[0017] WO 01/49687 discloses cyclohexene nucleic acids, their
hybridization behavior to RNA and the use in diagnostics and
therapy. Further cyclohexene or cyclohexene containing nucleic
acids are disclosed in Wang, J., et al., J. Am. Chem. Sci. 122
(2000) 8595-8602; Maurinsh, Y., et al., Chem. Eur. J. 5 (1999)
[0018] WO97/27317 and WO 02/072779 disclose various compounds for
nucleic acid labeling.
[0019] EP 0468352discloses nucleic acid derivatives comprising a
general formula that contains a six-membered ring but which contain
an additional methylene group at the C4 atom of the six-membered
ring. WO01/02417 and Jung., K.-E., Bioorg. Med. Chem. Lett. 9
(1999) 3407-3410 disclose a nucleotide monomer containing a
six-membered aza-sugar and oligomers containing them.
[0020] Compounds to be used for the incorporation of labels into
nucleic acids or to influence the properties of the modified
oligonucleotide have to be carefully selected as they may interfere
with base pairing, fail to provide a skeletal structure of
sufficient rigidity, provide largely hydrophobic structures
resulting in low water solubility, provide only limited amenability
to chemical modifications, or comprise mixtures of enantiomers.
Therefore, it was an object of the present invention to provide new
compounds to be used for the incorporation of labels into nucleic
acids or to influence their properties.
SUMMARY OF THE INVENTION
[0021] The present invention is related to compounds comprising
six-membered moieties, in particular specific compounds comprising
hexitol or cyclohexene moieties which may be used to build up
oligomeric compounds. The invention is further related to uses of
these oligomeric compounds for hybridization and as probes. In
addition, methods for the detection of a nucleic acid in a sample
are disclosed wherein the oligomeric compounds are used. The
hexitol structure provides as a particularly advantageous property
a hydrophilic skeletal structure. Moreover, the hexitol and the
cyclohexene structure is amenable to efficient chemical synthesis,
has an enhanced stability versus degradation by nucleases and is
stable against depurination.
[0022] Conventional techniques of molecular biology and nucleic
acid chemistry, which are within the skill of the art, are
explained in the literature. See, for example, Sambrook et al.,
Molecular Cloning: A Laboratory Manual, Cold Spring Harbor
Laboratory, Cold Spring Harbor, N.Y., 1989; Gait, M. J.,
Oligonucleotide Synthesis, ed. (1984); Hames, B. D., and Higgins,
S. J., Nucleic Acid Hybridization, eds. (1984); and a series,
Methods in Enzymology, Academic Press, Inc., all of which are
incorporated herein by reference. All patents, patent applications,
and publications mentioned herein, both supra and infra, are
incorporated herein by reference.
[0023] As is known in the art, a "nucleoside" is a base-sugar
combination. The base portion of the nucleoside is normally a
heterocyclic base. The two most common classes of such
(heterocyclic) bases are the purines and the pyrimidines which are
natural (heterocyclic) bases, i.e., they occur naturally. In more
detail, important natural (heterocyclic) bases are guanine,
cytosine, thymine, adenine, uracil or even methylcytosine.
[0024] "Nucleotides" are "nucleosides" that further include a
phosphate group covalently linked to the sugar portion of the
nucleoside. For those "nucleosides" that include a pentofuranosyl
sugar, the phosphate group can be linked to either the 2', 3' or 5'
hydroxyl moiety of the sugar. A "nucleotide" is the "monomeric
unit" of an "oligonucleotide", more generally denoted herein as
"oligomeric compound", or a "polynucleotide", more generally
denoted as a "polymeric compound". Another general expression
therefor is deoxyribonucleic acid (DNA) and ribonucleic acid
(RNA).
[0025] "Modified nucleotides" (or "nucleotide analogs") differ from
a natural "nucleotide" by some modification but still consist of a
(heterocyclic) base, a pentofuranosyl sugar, a phosphate portion,
(heterocyclic) base-like pentofuranosyl sugar-like and
phosphate-like portion or combination thereof. A pentofuranosyl
sugar-like portion is for example the 1,5 anhydrohexitol or
cyclohexenyl moiety. For example, a "label" may be attached to the
base portion of a "nucleotide" whereby a "modified nucleotide" is
obtained. A natural (heterocyclic) base in a "nucleotide" may also
be replaced by a non-natural (heterocyclic) base, i.e. a
(heterocyclic) base that does not occur in nature, whereby a
"modified nucleotide" is obtained as well. Then the "modified
nucleotide contains a (heterocyclic) base-like portion or
"base-analog" which resembles a natural (heterocyclic) base. A
"base analog" does not normally appear in nature, i.e. is
non-natural in other words, but can substitute for the ones which
do, despite minor differences in structure. According to the
invention, a heterocyclic base may be natural or non-natural. The
terms "modified nucleotide" or "nucleotide analog" are used
interchangeably in the present application.
[0026] A "modified nucleoside" (or "nucleoside analog") differs
from a natural nucleoside by some modification in the manner as
outlined above for a "modified nucleotide" (or a "nucleotide
analog").
[0027] A "non-nucleotide compound" is different from a natural
"nucleotide" but is in the sense of this invention still
capable--similar to a "nucleotide"--of being a "monomeric unit" of
an "oligomeric compound". Therefore, a "non-nucleotide compound"
has to be capable of forming an "oligomeric compound" with
"nucleotides". Even "non-nucleotide compounds" may contain a
base-like, pentofuranosyl sugar-like or a phosphate-like portion,
however, not all of them are present at the same time in a
"non-nucleotide compound".
[0028] According to the invention, an "oligomeric compound" is a
compound consisting of "monomeric units" which may be "nucleotides"
alone or "non-natural compounds", more specifically "modified
nucleotides" (or "nucleotide analogs") or "non-nucleotide
compounds", alone or combinations thereof. "Oligonucleotides" and
"modified oligonucleotides" or ("oligonucleotide analogs") are
subgroups of "oligomeric compounds" in the context of the
invention.
[0029] In the context of this invention, the term "oligonucleotide"
refers to "polynucleotides" formed from a plurality of
"nucleotides" as the "monomeric unit", i.e. an "oligonucleotide"
belongs to a specific subgroup of an "oligomeric compound" or
"polymeric compound" of ribonucleic acid (RNA) or deoxyribonucleic
acid (DNA) with "monomeric units". According to this invention, the
term "oligonucleotide" only includes "oligonucleotides" composed of
naturally occurring "nucleotides". The phosphate groups are
commonly referred to as forming the internucleoside backbone of the
"oligonucleotide". The normal linkage or backbone of RNA and DNA is
a 3' to 5' phosphodiester linkage.
[0030] A "modified oligonucleotide" or ("oligonucleotide analog")
belongs to another specific subgroup of the "oligomeric compounds"
that possesses one or more "nucleotides", one or more
"non-nucleotide compounds" or "modified nucleotides"as "monomeric
unit". Thus, the terms "modified oligonucleotide" or
("oligonucleotide analog") refers to structures that function in a
manner substantially similar to "oligonucleotides" and are used
interchangeably throughout the application. From a synthetic point
of view, a "modified oligonucleotide" or ("oligonucleotide analog")
can be for example made by chemical modification of
"oligonucleotides" by appropriate modification of the phosphate
backbone, ribose unit or the nucleic bases (Uhlmann and Peyman,
Chemical Reviews 90 (1990) 543; Verma S., and Eckstein, F., Annu.
Rev. Biochem. 67 (1998) 99-134). Representative modifications
include phosphorothioate, phosphorodithioate, methyl phosphonate,
phosphotriester or phosphoramidate inter-nucleoside linkages in
place of phosphodiester inter-nucleoside linkages; deaza or aza
purines and pyrimidines in place of natural purine and pyrimidine
bases, pyrimidine bases having substituent groups at the 5 or 6
position; prime bases having altered substituent groups at the 2, 6
or 8 positions or 7 position as 7-deazapurines; sugars having
substituent groups at, for example, their 2' position; or
carbocyclic or acyclic sugar analogs. Other modifications
consistent with the spirit of this invention are know to those
skilled in the art. Such "modified oligonucleotides" (or
"oligonucleotide analogs") are best described as being functionally
interchangeable with, yet structurally different from, natural
"oligonucleotides" (or synthetic "oligonucleotides" along natural
lines). In more detail, exemplary modifications are disclosed in
Verma, S., and Eckstein, F., Annu. Rev. Biochem. 67 (1998) 99-134
or WO 02/12263. In addition, modification can be made wherein
nucleoside units are joined through groups that substitute for the
internucleoside phosphate or sugar phosphate linkages. Such
linkages include those disclosed in Verma, S., and Eckstein, F.,
Annu. Rev. Biochem. 67 (1998) 99-134. When other than phosphate
linkages are utilized to link the nucleoside units, such structures
have also been described as "oligonucleosides".
[0031] "Oligomeric compounds" as "oligonucleotides" and "modified
oligonucleotides" according to the invention may be synthesized as
principally described in the art and known to the expert in the
field. Methods for preparing oligomeric compounds of specific
sequences are known in the art, and include, for example, cloning
and restriction of appropriate sequences where appropriate and
direct chemical synthesis. Chemical synthesis methods may include,
for example, the phosphotriester method described by Narang, S. A.,
et al., Methods in Enzymology 68 (1979) 90-98, the phosphodiester
method disclosed by Brown, E. L., et al., Methods in Enzymology 68
(1979) 109-151, the phosphoramidite method disclosed in Beaucage,
S. I., and Caruthers, M. H., et al., Tetrahedron Letters 22 (1981)
1859-1862, the H-phosphonate method disclosed in Garegg et al.,
Chem. Ser. 25 (1985) 280 and the solid support method disclosed in
U.S. Pat. No. 4,458,066.
[0032] As said above, a "nucleic acid" is a polymeric compound of
"nucleotides" as known to the expert skilled in the art. It is used
herein to denote a "nucleic acid" in a sample which should be
analyzed i.e. the presence, non-presence or amount thereof in a
sample should be determined. Therefore, in other words the "nucleic
acid" is the target and can therefore be also denoted as "target
nucleic acid". For example, if it has to be determined whether
blood contains the human immunodeficiency virus, the "target
nucleic" acid" is the nucleic acid of the human immunodeficiency
virus.
[0033] The term "primer" is used herein as known to the expert
skilled in the art and refers to "oligomeric compounds" primarily
to "oligonucleotides" but also to "modified oligonucleotide" that
are able to "prime" DNA synthesis by a template-dependent DNA
polymerase, i.e. the 3'-end of the e.g. oligonucleotide provides a
free 3'-OH group whereto further "nucleotides" may be attached by a
template-dependent DNA polymerase establishing 3' to 5'
phosphodiester linkage whereby deoxynucleoside triphosphates are
used and whereby pyrophosphate is released.
[0034] The term "probe" refers to synthetically or biologically
produced nucleic acids (DNA or RNA) which, by design or selection,
contain specific nucleotide sequences that allow them to hybridize
under defined predetermined stringencies specifically (i.e.
preferentially) to "target nucleic acids". A "probe" can be
identified as a "capture probe" meaning that it captures the target
nucleic acid so that it can be separated from undesirable materials
which might obscure its detection. Once separation is accomplished,
detection of the captured "target nucleic acid" can be achieved
using a suitable procedure. "Capture probes" are often already
attached to a solid phase. A specific example therefor is the
microarray situation wherein a multitude of "capture probes" are
attached to a "solid phase" which "captures" labeled cRNA or
cDNA.
[0035] "Alkyl" groups are preferably chosen from alkyl groups
containing from 1 to 10 carbon atoms, either arranged in linear,
branched or cyclic form. The actual length of the alkyl group will
depend on the stearic situation at the specific position where the
alkyl group is located. If there are stearic constraints, the alkyl
group will generally be smaller, the methyl and ethyl group being
most preferred.
[0036] "Alkenyl" groups are preferably selected from alkenyl groups
containing from 2 to 10 carbon atoms. For the selections similar
considerations apply as for alkyl groups. They also can be linear,
branched and cyclic. The most preferred alkenyl group is the
ethylene group. There can be more than one double bond in the
alkenyl group.
[0037] "Alkynyl" groups have preferably from 2 to 10 carbon atoms.
Again, those carbon atoms can be arranged in linear, branched and
cyclic manner. There can be more than one triple bond in the
alkynyl. The most preferred alkynyl group is propynl.
[0038] All "alkyl", "alkenyl" and "alkynyl" groups can be either
unsubstituted or substituted. Substitution by hetero atoms as
outlined above will help to increase solubility in aqueous
solutions.
[0039] A"protecting group" is a chemical group that is attached to
a functional moiety (for example to the oxygen in a hydroxyl group,
the nitrogen in an amino group or the sulfur in a thiol group,
thereby replacing the hydrogen) to protect the functional group
from reacting in an undesired way. A protecting group is further
defined by the fact that it can be removed without destroying the
biological activity of the molecule formed, here the binding of the
nucleic acid binding compound to a nucleic acid. Suitable
protecting groups are known to a man skilled in the art. Preferred
protecting groups according to this invention are
fluorenylmethoxycarbonyl (FMOC), dimethoxytrityl (DMT),
monomethoxytrityl-, trifluoroacetyl-, levulinyl-, or silyl-groups.
Preferred protecting groups for example for hydroxyl groups at the
5'-end of a nucleotide or oligonucleotide are selected, from the
trityl groups, for example dimethoxytrityl (DMT). Preferred
protecting groups at exocyclic amino groups in Formula I are acyl
groups, most preferred the benzoyl group (Bz), phenoxyacetyl or
acetyl or formyl, and the amidine protecting groups as e.g. the
N,N-dialkylformamidine group, preferentially the dimethyl-,
diisobutyl-, and the di-n-butylformamidine group. Preferred
O-protecting groups are the aroyl groups, the diphenylcarbamoyl
group, the acyl groups, and the silyl groups. Among these most
preferred is the benzoyl group. Preferred silyl groups are the
trialkylsilyl groups, like, trimethylsilyl, triethylsilyl and
tertiary butyl-dimethyl-silyl. Another preferred silyl group is the
trimethylsilyl-oxy-methyl group (TOM) (WO99/09044). Further,
preferred protecting groups are ortho nitro-benzyl,
2-(4-nitrophenyl)ethoxycarbonyl (NPEOC), photoactivable compounds
as 2-nitrophenyl-propyloxy-carbonyl (NPPOC) (Giegrich et al.,
Nucleosides & Nucleotides 17 (1998) 1987) and
allyloxycarbonyl.
[0040] "Labels", often referred to as "reporter groups", are
generally groups that make a nucleic acid, in particular the
"oligomeric compound" or the "modified oligonucleotide" according
to the invention, as well as any nucleic acids bound thereto
distinguishable from the remainder of the liquid, i.e. the sample
(nucleic acids having attached a "label" can also be termed labeled
nucleic acid binding compounds, labeled probes or just probes).
"Haptens (such as biotin or digoxigenin), enzymes (such as alkaline
phosphatase or peroxidase) or fluorescent dyes (such as fluorescein
or rhodamine) have, among others, mainly proven to be suitable as
non-radioactive indicator molecules or in other words as
non-radioactive "labels". These "signal groups" or "labels" can be
attached to or incorporated in nucleic acids by various methods.
Preferred "labels" according to the invention are dyes as a
fluorescein dye, a rhodamine dye, a cyanine dye, and a coumarin dye
or haptens as biotin. By general definition, a "hapten" is a small
molecule which is not by itself an immunogen (can cause an immune
response), but has at least one element of an antigen and can
combine with an antibody or another larger carrier molecule to
become immunogenic.
[0041] The term "linking moiety" refers to a group of atoms which
connect the moiety intended to be used (e.g. the "solid phase" or
the "label") to the position of attachment at the "nucleotide",
"modified nucleotide" or "non-nucleotide compound". This can be
e.g. the base, sugar or phosphate moiety of a "nucleotide " or
"modified nucleotide" or the base-like, sugar-like or
phosphate-like moiety of a "non-nucleotide compound" or "modified
nucleotide". The "linking moiety" will provide flexibility such
that the "oligomeric compound" according to the invention, in
particular the "modified oligonucleotide", can bind the "target
nucleic acid" to be determined without major hindrance by the
"solid phase" or "label". "Linking moieties", especially those that
are not hydrophobic, for example based on consecutive
ethylenoxy-units as disclosed in DE 3943522, are known to an expert
skilled in the art. In the contest of the invention a linking
moiety contains a reactive group which is the point of attachment
to e.g. the "solid phase" or "label".
[0042] According to the invention, a "solid phase" may be
controlled pore glass (CPG), polystyrene or silica gel as used for
oligonucleotide synthesis.
[0043] As used herein, "fluorescence resonance energy transfer
relationship" and similar terms refer to adjacent hybridization of
an "oligomeric compound" labeled with a "donor fluorescent label"
and another "oligomeric compound" labeled with an "acceptor
fluorescent label" to a "target nucleic acid" such that the "donor
fluorescent label" can transfer resonance energy to the "acceptor
fluorescent label" such that the "acceptor fluorescent label"
produces a measurable fluorescence emission. If the "donor
fluorescent label" and "acceptor fluorescent label" are spaced
apart by too great a distance, the "donor fluorescent label" cannot
transfer resonance energy to the "acceptor fluorescent label" such
that the "acceptor fluorescent label" emits measurable
fluorescence, and hence the "donor fluorescent label" and "acceptor
fluorescent label" are not in resonance energy transfer
relationship.
[0044] By "array" is meant an arrangement of addressable locations
on a device (see e.g. U.S. Pat. No. 5,143,854, U.S. Pat. No.
6,022,963, U.S. Pat. No. 6,156,501, WO 90/15070, WO 92/10092). The
locations can be arranged in two dimensional arrays, three
dimensional arrays, or other matrix formats. The number of
locations can range from several to at least hundreds of thousands.
Most importantly, each location represents a totally independent
reaction site. Each location carries a nucleic acid as e.g. an
"oligomeric compound", which can serve as a binding partner for a
second nucleic acid, in particular a target nucleic acid. Methods
for the manufacturing thereof are described in EP-A-0 476 014 and
Hoheisal, J. D., TIBTECH (1997), Vol. 15, 465-469, WO 89/10977, WO
89/11548, U.S. Pat. No. 5,202,231, U.S. Pat. No. 5,002,867, WO
93/17126). Further development has provided methods for making very
large arrays of oligonucleotide probes in very small areas. (U.S.
Pat. No. 5,143,854, WO 90/15070, WO 92/10092). Microfabricated
arrays of large numbers of oligonucleotide probes, called "DNA
chips" offer great promise for a wide variety of applications (see
e.g. U.S. Pat. No. 6,156,501 and U.S. Pat. No. 6,022,963).
[0045] In the context of this invention, "hybridization" shall mean
hydrogen bonding, which may be Watson-Crick, Hoogsteen or reversed
Hoogsteen hydrogen bonding, between complementary nucleotides. For
example, adenine and thymine are complementary nucleobases which
pair through the formation of hydrogen bonds. "Complementary," as
used herein, also refers to sequence complementarity between two
nucleotides. For example, if a nucleotide at a certain position of
an oligonucleotide is capable of hydrogen bonding with a nucleotide
of the same position of a DNA or RNA molecule, then the
oligonucleotide and the DNA or RNA are considered to be
complementary to each other at that position. The oligonucleotide
and the DNA or RNA are complementary to each other when a
sufficient number of corresponding positions in each molecule are
occupied by nucleotide which can hydrogen bond with each other.
Thus, "specifically hybridizable" and "complementary" are terms
which are used to indicate a sufficient degree of complementarity
such that stable and specific binding occurs between the
oligonucleotide and the DNA or RNA target. It is understood that an
oligonucleotide need not be 100% complementary to its target DNA
sequence to be specifically hybridizable. An oligonucleotide is
specifically hybridizable when binding of the oligonucleotide to
the target DNA or RNA molecule interferes with the normal function
of the target DNA or RNA, and there is a sufficient degree of
complementarity to avoid non-specific binding of the
oligonucleotide to non-target sequences under conditions in which
specific binding is desired, i.e. under physiological conditions in
the case of in vivo assays or therapeutic treatment, or in the case
of in vitro assays, under conditions in which the assays are
performed.
[0046] A "reactive group" is a group that is capable of reacting
with and connecting to another group on another molecule. Preferred
"reactive groups" are hydroxyl (--OH), carboxyl, amino or thiol
group.
DESCRIPTION OF THE FIGURES
[0047] FIG. 1: Synthesis of a phoshoramidite derivative comprising
uracil as the base, a linking moiety with a FMOC protected amino
group as reactive group and a tetrahydropyran as the six-membered
ring
[0048] FIG. 2: Synthesis of
1,5-anhydro-2-(5-(6-biotinamido-hexanoate
amidoallyl-uracil-1yl)-2,3-dideoxy-D-arabino-hexitol 6
triphosphate
[0049] FIG. 3: Synthesis of a triphosphate derivative comprising
adenine as the base, biotin as the hapten, a linking moiety and a
tetrahydropyran as the six-membered ring similar to the compound of
FIG. 2
[0050] FIG 4: Overview of the substances synthesized for the
incorporation studies in examples 1.3.1
[0051] FIG. 5: Dot blot of incorporation studies (see example
1.3.1)
[0052] FIG. 6: Dot blot of incorporation studies (see example
1.3.1)
[0053] FIG. 7: Image of a glass array after hybridization with
Bio-h-dUTP labeled cDNA derived from rat tissue (Squares: negative
control spots, Circles: probes for neuronal cannabinoid receptor
expressed in liver, kidney; Alpha-1 microglobulin/bikunin ambp
expressed in liver and Gapd expressed in all at tissues)
DETAILED DESCRIPTION OF THE INVENTION
[0054] In an embodiment of the invention, compounds are provided
that are capable of being incorporate into nucleic acids by
chemical or enzymatic synthesis. Therefore, in an embodiment of the
invention, a compound is provided according to Formula I: ##STR1##
wherein L is a linking moiety, [0055] wherein B is a heterocyclic
base, [0056] wherein R.sup.1 is independent from R.sup.2, R.sup.3,
R.sup.4, R.sup.5, R.sup.5a, R.sup.5b and R.sup.6 wherein R.sup.1 is
selected from the group consisting of a protecting group, a label,
a solid phase, and --H, [0057] wherein R.sup.2 is independent from
R.sup.1, R.sup.3, R.sup.4, R.sup.5, R.sup.5a, R.sup.5b and R.sup.6
wherein R.sup.2 is selected from the group consisting of --H and
--OR.sup.8. [0058] wherein R.sup.3 is independent from R.sup.1,
R.sup.2, R.sup.4, R.sup.5, R.sup.5a, R.sup.5b and R.sup.3 wherein
R.sup.3 is selected from the group consisting of a protecting
group, a linking group, a linking moiety covalently coupled to a
solid phase, a phosphoramidite, a H-phosphonate, and a
triphosphate, [0059] wherein R.sup.4 is independent from R.sup.1,
R.sup.2, R.sup.3, R.sup.5, R.sup.5a, R.sup.5b and R.sup.6 and
R.sup.4 is --H, --OH, alkyl, halogen, --O--R.sup.5, --S--R.sup.5,
NR.sup.5R.sup.5a, a label or a linking moiety covalently coupled to
a solid phase, [0060] wherein R.sup.6 is independent from R.sup.1,
R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.5a, and R.sup.5b, and
wherein R.sup.6 is selected from the group consisting of --H, a
protecting group, a linking moiety covalently coupled to a solid
phase, a phosphoramidite, and a H-phosphonate, [0061] wherein the
dotted line between the Cl atom of the six-membered ring and Y
represents the optional presence of a double bond whereby Y is
CR.sup.5a when the double bond is present, or Y is selected from
the group consisting of O, S, NR.sup.5 and CR.sup.5aR.sup.5b when
the double bond is absent, [0062] whereby R.sup.5, R.sup.5a and
R.sup.5b are independent from one another and independent from
R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.6 and R.sup.5 is
independently selected from alkyl, alkenyl, alkinyl, aryl, acyl, a
protecting group or --H, and R.sup.5a and R.sup.5b are
independently selected from alkyl, alkenyl, alkinyl, aryl, acyl, or
--H.
[0063] Preferably, R.sup.6 and R.sup.3 are not both a solid phase,
both a phosphoramidite, both a H-phosphonate, or a phosphoramidite
and a H-phosphonate, or a solid phase and a phosphoramidite, or a
solid phase and a H-phosphonate. Preferably, when one residue
selected from the group consisting of R.sup.1, R.sup.3 or R.sup.6
is a solid phase then the other two residues selected from the
group consisting of R.sup.1, R.sup.3 or R.sup.6 are not a solid
phase. The expert skilled in the art is aware of the compounds
exemplified in Formula I that do not make sense with regard to
their property of being capable of being incorporated into nucleic
acids.
[0064] In another preferred embodiment of the invention, R.sup.4 in
the Formula I of the compound according to the invention is --H or
OH.
[0065] In a preferred embodiment, the heterocyclic base in Formula
I of the compound according to the invention is a natural or a
non-natural heterocyclic base. Preferably, the natural heterocyclic
base is adenine, guanine, cytosine, thymine, adenine, uracil or
methyl-cytosine. More preferably the natural heterocyclic base is a
pyrimidine or a 7-deazapurine, more preferably a uracil.
Preferably, the C5 atom of pyrimidines, in particular uracil, or
the 7-position of 7-deazapurines is the point of attachment of the
linking moiety L.
[0066] The nature of the linking moiety L in Formula I is designed
to space the group R.sup.1 a sufficient distance from B such that
[0067] (a) the compound according to the invention is able to be
recognized by a polymerase and incorporated in a growing nucleic
acid chain during a polymerization reaction, when R.sup.3 is a
triphosphate; [0068] (b) the compound according to the invention
once incorporated in a nucleic acid chain, is preferably able to
base pair to a complementary base, that is the hybridization
ability of the probe produced by the amplification reaction should
preferably not be significantly affected; and [0069] (c) the group
R.sup.1 is held away from the target nucleic acid to avoid
interactions or quenching effects if no intercalation of the group
R.sup.1 is intended.
[0070] In another preferred embodiment, the linking moiety L in the
compound according to the invention comprises carbon, oxygen or
nitrogen atoms and a reactive group. Preferably the reactive group
is a carboxyl, amino, thiol or hydroxyl group. L is preferably an
optionally substituted and optionally interrupted hydrocarbon chain
derivative and is preferably more than 2 carbon atoms, preferably
more than 3 carbon atoms and preferably up to 30 carbon atoms long.
The optional interruptions are --CH.dbd.CH--, --C.dbd.C--, --NH--,
--CONH--, --S--, --O--, --SO.sub.2--, ureido, phenylene,
cyclohexylene and groups of the formula --CH.dbd.CH--NH--,
--C.dbd.CH--CH.sub.2--NH--, --NH--C(.dbd.NH.sub.2).sup.+--,
--NH--C(.dbd.NH.sub.2).sup.+--NH-- and --C(.dbd.O)--O--. For the
avoidance of doubt 1,2-, 1,3- and 1,4-phenylene groups are
respectively regarded as 2, 3 and 4 carbon atoms long. The optional
interruptions are incorporated in order to facilitate the synthesis
of the chain and/or to provide more hydrophilic elements to
maintain the linear structure of the chain and prevent it folding
in on itself. Preferably, the linking moiety is a derivative of a
C.sub.1-C.sub.10 alkyl, a C.sub.1-C.sub.10 alkenyl, a
C.sub.2-C.sub.10 alkynyl, an aminoallyl or an acrylamido moiety.
More preferably, the linking moiety is a derivative of a
C.sub.2-C.sub.10, C.sub.3-C.sub.10 or C.sub.4-C.sub.10 alkyl.
[0071] The site of attachment of the linking moiety L on the
nucleoside triphosphate is on the base moiety. In order not to
interfere with hybridization it is preferable that L should be
joined to those atoms that are believed to be exposed in the major
groove of the DNA double helix that is C5, C6 or the amino group on
C4 of cytosine; C5, C6 or the oxygen attached to C4 of uridine; C5
methyl, C6 or the oxygen attached to C4 of thymine; N7, C8 or the
amino group on C6 of adenine; N7, C8 or the oxygen attached to C6
of guanine or C7 of deaza-adenine or deaza-guanine.
[0072] In another embodiment, R.sup.1 is independent from R.sup.2,
R.sup.3, R.sup.4, R.sup.5, R.sup.5a, R.sup.5b and R.sup.6 wherein
R.sup.1 is a protecting group, a label, or a solid phase. In
another embodiment, R.sup.1 is independent from R.sup.2, R.sup.3,
R.sup.4, R.sup.5, R.sup.5a, R.sup.5b and R.sup.6 wherein R.sup.1 is
a label or a solid phase. In another embodiment, R.sup.1 is
independent from R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.5a,
R.sup.5b and R.sup.6 wherein R.sup.1 is a protecting group or a
label. In the most preferred embodiment, R.sup.1 in the Formula I
of the compound according to the invention is a label.
[0073] Preferably, the label is a dye or a hapten, preferably a
fluorescent dye. Preferably, the dye is selected from the group
consisting of a fluorescein dye, a rhodamine dye, a cyanine dye, a
coumarin dye, and an azo dye. Preferably, the hapten is biotin.
[0074] According to the invention, preferred compounds are
compounds which can be easily incorporated into nucleic acids by
the use of enzymes. Therefore, in a very preferred embodiment,
R.sup.3 is a triphosphate, R.sup.2 is --OR.sup.6, wherein R.sup.6
is --H, and R.sup.4 is --H or --OH in the Formula I of the compound
according to the invention. In another very preferred embodiment of
the invention, Y is O, S, or CR.sup.5aR.sup.5b when the double bond
is absent in the Formula I of the compounds according to the
invention are represented by Formula II. ##STR2##
[0075] The term "H/OH" shall denote that --H or --OH may be
present, in other words it could be described as residue K which
can be --H or --OH.
[0076] In another very preferred embodiment of the invention,
cyclohexene derivatives are provided, i.e. the dotted line between
the Cl atom of the six-membered ring and Y represents the presence
of a double bond in the Formula I of the compound according to the
invention whereby Y is CR.sup.5a and R.sup.5a is independently
selected from alkyl, alkenyl, alkinyl, aryl, acyl, or --H.
Preferably, R.sup.5a is --H.
[0077] In another preferred embodiment of the invention, a
phosphoramidite is provided suitable for chemical synthesis of
oligomeric compounds according to the invention. This is more
specifically a compound according to the invention with Formula I,
wherein R.sup.2 is independent from R.sup.1, R.sup.3, R.sup.4,
R.sup.5, R.sup.5a, R.sup.5b, and R.sup.6 and R.sup.2 is --OR.sup.6
wherein R.sup.6 is a phosphoramidite; and R.sup.3 is independent
from R.sup.1, R.sup.2, R.sup.4, R.sup.5, R.sup.5a, R.sup.5b, and
R.sup.6 and R.sup.3 is a protecting group or a solid phase
covalently coupled to a linking moiety. Preferably, R.sup.3 is a
protecting group.
[0078] In another embodiment of the invention, an oligomeric
compound comprising a monomeric unit with the formula S-B-L-R.sup.7
is provided wherein S is a moiety comprising a six-membered ring, B
is a heterocyclic base, L is a linking moiety, and R.sup.7 is a
label, a protecting group or a solid phase. Preferably, the
six-membered ring is a derivative of cyclohexane, cyclohexene,
tetrahydropyran, tetrahydrothiopyran or piperidine. Preferably,
R.sup.7 is a label or a solid phase, more preferably R.sup.7 is a
label.
[0079] In a preferred embodiment of the invention, an oligomeric
compound with an monomeric unit with Formula III is provided:
##STR3## wherein L is a linking moiety covalently and B is a
heterocyclic base, [0080] wherein R.sup.7 is independent from
R.sup.5, R.sup.5a, R.sup.5b, R.sup.8, R.sup.9, R.sup.10 and
R.sup.13 wherein R.sup.7 is selected from the group consisting of a
protecting group, a label, a solid phase, and --H, [0081] wherein
R.sup.8 is independent from R.sup.5, R.sup.5a, R.sup.5b, R.sup.7,
R.sup.8, R.sup.10 and R.sup.11 wherein R.sup.8 is selected from the
group consisting of --H and --OR.sup.11. [0082] wherein R.sup.9 and
R.sup.11 are independent from each other and independent from
R.sup.5, R.sup.5a, R.sup.5b, R.sup.7, R.sup.8 or R.sup.10, and
wherein R.sup.9 and R.sup.11 are selected from the group consisting
of --H, a linking moiety covalently coupled to a solid phase, a
phosphate, a phosphodiester and a nucleotide, a modified
nucleotide, an oligonucleotide or a modified oligonucleotide.
[0083] wherein R.sup.10 is independent from R.sup.5, R.sup.5a,
R.sup.5b, R.sup.7, R.sup.8, R.sup.9 and R.sup.11 and R.sup.10 is
--H, --OH, alkyl, halogen, --O--R.sup.5, --S--R.sup.5,
NR.sup.5R.sup.5a, a label or a linking moiety covalently coupled to
a solid phase, [0084] wherein the dotted line between the Cl atom
of the six-membered ring and Y represents the optional presence of
a double bond whereby Y is CR.sup.5a when the double bond is
present, or Y is selected from the group consisting of O, S,
NR.sup.5 and CR.sup.5aR.sup.5b when the double bond is absent,
[0085] whereby R.sup.5, R.sup.5a and R.sup.5b are independent from
one another and independent from R.sup.7, R.sup.8, R.sup.9,
R.sup.10 and R.sup.11 and R.sup.5 is independently selected from
alkyl, alkenyl, alkinyl, aryl, acyl, a protecting group or --H, and
R.sup.5a and R.sup.5b are independently selected from alkyl,
alkenyl, alkinyl, aryl, acyl, or --H.
[0086] Preferably, R.sup.8 and R.sup.9 are not both --H or R.sup.9
and R.sup.11 are not both --H when R.sup.8 is OR.sup.11 to exclude
the case that only a monomer is considered. The expert skilled in
the art is aware of the compounds that would be senseless according
to the invention, i.e. R.sup.9 and R.sup.11 are not both phosphate
or --H and a phosphate. Preferably, when one residue selected from
the group consisting of R.sup.7, R.sup.9, R.sup.10 or R.sup.11 is a
solid phase or a linking moiety covalently coupled to a solid phase
then the other residues selected from the group consisting of
R.sup.7, R.sup.9, R.sup.10 or R.sup.11 are not a solid phase or a
linking moiety covalently coupled to a solid phase.
[0087] The phosphate or triphosphate residues may also be modified
phosphate or analogs of phosphate as e.g. thiophosphates or
.alpha.-thio-triphosphates.
[0088] In a preferred embodiment, the heterocyclic base in the
Formula III of the oligomeric compound according to the invention
is a natural or a non-natural heterocyclic base. Preferably, the
natural heterocyclic base is adenine, guanine, cytosine, thymine,
uracil or methyl-cytosine. More preferably the natural heterocyclic
base is a pyrimidine or a 7-deazapurine, more preferably an uracil.
Preferably, the C5 atom of pyrimidines, in particular uracil, or
the 7-position of 7-deazapurine is the point of attachment of the
linking moiety L.
[0089] Preferably, R.sup.7 is a label or a solid phase, more
preferably R.sup.7 is a label.
[0090] The nature of the linking moiety L in Formula I is designed
to space the group R.sup.1 a sufficient distance from B such that
[0091] (a) the compound according to the invention is able to be
recognized by a polymerase and incorporated in a growing nucleic
acid chain during a polymerization reaction, when R3 is a
triphosphate; [0092] (b) the compound according to the invention
once incorporated in a nucleic acid chain, is preferably able to
base pair to a complementary base, that is the hybridization
ability of the probe produced by the amplification reaction should
preferably not be significantly affected; and [0093] (c) the group
R.sup.1 is held away from the target nucleic acid to avoid
interactions or quenching effects if no intercalation of the group
R.sup.1 is intended.
[0094] In another preferred embodiment, the linking moiety L in the
compound according to the invention comprises carbon, oxygen or
nitrogen atoms and a reactive group. Preferably the reactive group
is a carboxyl, amino, thiol or hydroxyl group. L is preferably an
optionally substituted and optionally interrupted hydrocarbon chain
derivative and is preferably more than 2 carbon atoms, preferably
more than 3 carbon atoms and preferably up to 30 carbon atoms long.
The optional interruptions are --CH.dbd.CH--, --C.dbd.C--, --NH--,
--CONH--, --S--, --O--, --SO.sub.2--, ureido, phenylene,
cyclohexylene and groups of the formula --CH.dbd.CH--NH--,
--C.dbd.CH--CH.sub.2--NH--, --NH--C(.dbd.NH.sub.2).sup.+--,
--NH--C(.dbd.NH.sub.2).sup.+--NH-- and --C(.dbd.O)--O--. For the
avoidance of doubt 1,2-, 1,3- and 1,4-phenylene groups are
respectively regarded as 2, 3 and 4 carbon atoms long. The optional
interruptions are incorporated in order to facilitate the synthesis
of the chain and/or to provide more hydrophilic elements to
maintain the linear structure of the chain and prevent it folding
in on itself. Preferably, the linking moiety is a derivative of a
C.sub.1-C.sub.10 alkyl, a C.sub.1-C.sub.10 alkenyl, a
C.sub.2-C.sub.10 alkynyl, an aminoallyl or an acrylamido moiety.
More preferably, the linking moiety is a derivative of a
C.sub.2-C.sub.10, C.sub.3-C.sub.10 or C.sub.4-C.sub.10 alkyl.
[0095] The site of attachment of the linking moiety L on the
nucleoside triphosphate is on the base moiety. In order not to
interfere with hybridization it is preferable that L should be
joined to those atoms that are believed to be exposed in the major
groove of the DNA double helix that is C5, C6 or the amino group on
C4 of cytosine; C5, C6 or the oxygen attached to C4 of uridine; C5
methyl, C6 or the oxygen attached to C4 of thymine; N7, C8 or the
amino group on C6 of adenine; N7, C8 or the oxygen attached to C6
of guanine or C7 of deaza-adenine or deaza-guanine.
[0096] In another preferred embodiment, R.sup.7 in Formula III of
the compound according to the invention is a label. Preferably, the
label is a dye or a hapten, preferably a fluorescent dye. More
preferably, the dye is selected from the group consisting of a
fluorescein dye, a rhodamine dye, a cyanine dye, a coumarin dye,
and an azo dye. Preferably, the hapten is biotin.
[0097] In a very preferred embodiment of the invention, the
compound is a modified oligonucleotide, whereby in Formula III of
the compound according to the invention R.sup.8 is --OR.sup.11, and
R.sup.9 and R.sup.11 is an oligonucleotide or a modified
oligonucleotide and R.sup.10 is --H or --OH.
[0098] In a preferred embodiment of the invention, Y is O, S, or
CR.sup.5aR.sup.5b when the double bond is absent. In a very
preferred embodiment of the invention, the compound according to
the invention is a hexitol derivative, i.e. Y is O in formula III
of the compound according to the invention when the double bond is
absent.
[0099] In a very preferred embodiment of the invention, the
compound according to the invention is a cyclohexene derivative,
i.e. the dotted line between the Cl atom of the six-membered ring
and Y represents the presence of a double bond whereby Y is
CR.sup.5a and R.sup.5a is independently selected from alkyl,
alkenyl, alkinyl, aryl, acyl, or --H. Preferably, R.sup.5a is
--H.
[0100] For use in the formats used in the LightCycler.RTM.
Instrument, the compound according to the invention will be
preferably directed to the 3'- or 5'-end of the oligomeric compound
during the synthesis thereof.
[0101] Preferably for use in the TaqMan.RTM. format, the label
R.sup.7 attached to the oligomeric compound according to the
invention may be located internally in the oligomeric compound
according to the invention, at the 5'-end or the 3'-end of the
oligomeric compound according to the invention.
[0102] The label is preferably a fluorescent label, preferably
fluorescein or a rhodamine dye. The oligomeric compound according
to the invention may further comprise other labels wherein the
emission wavelengths of one of the labels overlap the absorption
wavelengths of another one of the labels. Preferably, the
oligomeric compound further comprises a second label acting as a
quenching agent that quenches the fluorescence emission of the
fluorescent label, which can be fluorescein. Preferably the
quenching agent is a fluorescent rhodamine or cyanine dye or a
non-fluorescent label as dabcyl ("Dark Quencher"). In the most
preferred embodiment, the oligomeric compound according to the
invention cannot be extended enzymatically to be used as probe in
the TaqMan.RTM. format as principally set out in U.S. Pat. No.
5,210,015, U.S. Pat. No. 5,487,972 or U.S. Pat. No. 5,804,375.
Preferably, the monomeric unit at the 3'-end of the oligomeric
compound is a 2',3'-dideoxynucleotide or a 3'-phosphorylated
nucleotide. Preferably for use in the TaqMan.RTM. format, the
monomeric unit according to the invention with a label, preferably
a fluorescent label, as well as a second monomeric unit with
another label, preferably a second fluorescent label, may be
located internally in the oligomeric compound according to the
invention or at the 5'-end and/or the 3'-end of the oligomeric
compound according to the invention. Therefore, in a preferred
embodiment of the invention, the oligomeric compound according to
the invention comprises a modified oligonucleotide that comprises a
monomeric unit that is a linking moiety with a second label
attached to a nucleotide, or a linking moiety with a second label
attached to a modified nucleotide or a non-nucleotide compound.
[0103] Preferably, the second label is a second dye which is
preferably a fluorescent and is preferably selected from the group
consisting of a fluorescein dye, a rhodamine dye, a cyanine dye, a
coumarin dye, and an azo dye.
[0104] Preferably, the oligomeric compound according to the
invention cannot be extended enzymatically. Therefore, preferably
the monomeric unit at the 3'-end of the oligomeric compound is a
2',3'-dideoxynucleotide or a 3'-phosphorylated nucleotide .
[0105] The expert skilled in the art acknowledges the fact that the
six-membered ring of the compound according to the invention or of
the oligomeric compound according to the invention may carry
further substituents and still be functional in the methods
according to the invention. In particular the six-membered ring but
also the linking moiety may carry further halogen, thiol, hydroxyl,
amino, alkyl, alkenyl, alkynyl, aryl substituents whereby alkyl,
alkenyl, alkynyl, aryl substituents may optionally contain
heteroatoms or heteroaryl substituents optionally substituted with
further substituents. Preferred is also a further substituent at
the C5 atom of the six-membered ring of Formula I or III which is
selected from alkyl, alkenyl, alkynyl, aryl, alkoxy, aminoalkyl,
halogen, azido, hydroxyl, carboxyl or amino moiety. these compounds
may be tested whether they can be used in the methods or uses
according to the invention by e.g. simple hybridization experiments
with complementary oligonucleotides as described, in the assay
formats used in the LightCycler.RTM. instrument or in the
TaqMan.RTM. instrument or in the chemical synthesis method
according to the invention making use of phosphoramidite or solid
phase-linked compounds.
[0106] The oligomeric compound according to the invention may be
synthesized as principally described in the art and known to the
expert in the field, particularly preferred building blocks
therefor are the compounds according to the invention. Methods for
preparing oligomeric compounds as oligonucleotides and modified
oligonucleotides of specific sequences are known in the art, and
include, for example, cloning and restriction of appropriate
sequences and direct chemical synthesis. Chemical synthesis methods
may include, for example, the phosphotriester method described by
Narang, S. A., et al., Methods in Enzymology 68 (1979) 90-98, the
phosphodiester method disclosed by Brown, E. L., et al., Methods in
Enzymology 68 (1979) 109-151, the phophoramidite method disclosed
in Beaucage, et al., Tetrahedron Letters 22 (1981) 1859, the
H-phosphonate method disclosed in Garegg et al., Chem. Ser. 25
(1985) 280 and the solid support method disclosed in U.S. Pat. No.
4,458,066. Particularly preferred is the phosphoramidite method.
Therefore, in another embodiment of the invention, a method for the
chemical synthesis of an oligomeric compound according to the
invention is provided, comprising the steps of
[0107] (a) providing a compound according to the invention, wherein
R.sup.2 is --OR.sup.6 and R.sup.6 is phosphoramidite and R.sup.3 is
a protecting group, [0108] (b) providing an --OH group of a
nucleoside or a modified nucleoside bound to a solid phase by
another --OH group, or providing an --OH group of a oligonucleotide
or a modified oligonucleotide bound to a solid phase by another
--OH group of the nucleotide or modified nucleotide at the 3'-end
of the oligonucleotide or the modified oligonucleotide, [0109] (c)
reacting the phosphorous atom of the phosphoramidite with the free
OH group to form a phosphite ester and oxidizing the phosphite
ester to a phosphotriester, [0110] (d) optionally reacting any
unreacted --OH group of step (C) with another compound to prevent
any further reactions of the unreacted 5'-OH group of step (c) in
the following steps ("capping"-reaction). [0111] (e) optionally
repeating steps (c) to (d) with phosphoramidite derivates of
nucleosides, modified nucleosides or a compound according to the
invention, wherein R.sup.2 is --OR.sup.6 and R.sup.6 is
phosphoramidite and R.sup.3 is a protecting group after removal of
the hydroxyl protecting group of the product of step (d) to provide
a free --OH group, and [0112] (f) cleaving the oligomeric compound
from the solid phase, removing the protecting groups and thereby
converting the phosphotriester, and [0113] (g) isolating the
oligomeric compound.
[0114] Methods for performing these reaction steps are known to the
expert skilled in the art.
[0115] In another preferred embodiment of the invention, a method
for the enzymatic synthesis of an oligomeric compound according to
the invention is provided comprising the steps of [0116] (a)
incubating a compound according to the invention, wherein R.sup.3
of said compound is a triphosphate, with an OH group, which is
preferably extendable, of the nucleotide or modified nucleotide at
the 3'-end of a polynucleotide, oligonucleotide or a modified
oligonucleotide in the presence of a terminal transferase or a
polymerase, whereby the compound is attached to the OH group, which
is preferably extendable, whereby pyrophosphate is released, [0117]
(b) optionally incubating the OH group, which is preferably
extendable at be 3'-end of the product of step (a) with a
nucleoside triphosphate or a modified nucleoside triphosphate
presence of terminal transferase or a polymerase, whereby the
nucleotide or modified nucleotide is attached to the OH group,
which is preferably extendable, whereby pyrophosphate is released,
[0118] (c) optionally repeating step (a) or (b) or both, and [0119]
(d) isolating the oligomeric compound.
[0120] In the case of the use of terminal transferase, step (b) and
(c) of the method for the enzymatic synthesis according to the
invention are preferably not performed.
[0121] In another preferred embodiment of the invention, a
composition for analyzing interactions between target nucleic acids
and oligomeric compounds comprising an array of a plurality of
oligomeric compounds according to the invention having different
sequences. Most preferred, the oligomeric compound is an oligomeric
compound according to the invention, i.e. it is a compound of
Formula III wherein R.sup.7 is the solid phase or R.sup.9, R.sup.10
or R.sup.11 is a linking moiety covalently coupled to the solid
phase, i.e. these residues are the point of attachment to the solid
phase.
[0122] In a preferred embodiment of the invention, a compound
according to the invention with Formula I, wherein R.sup.2 is
--OR.sup.6 and R.sup.6 is a phosphoramidite, and R.sup.3 is a solid
phase covalently coupled to a linking moiety or a protecting group,
is used for the chemical synthesis of an oligomeric compound
according to the invention.
[0123] In another preferred embodiment of the invention, a compound
according to the invention is used for the labeling of nucleic
acids, i.e. the enzymatic incorporation of labeled modified
nucleotides into nucleic acids whereby the method for the enzymatic
synthesis of an oligomeric compound according to the invention is
used employing triphosphate derivatives of the compound according
to the invention. In more detail, a compound according to the
invention with Formula I, wherein R.sup.3 is a triphosphate,
R.sup.2 is --OR.sup.6, wherein R.sup.6 is --H, and R.sup.4 is --H
or --OH is used for the enzymatic synthesis of a labeled nucleic
acid, i.e. an oligomeric compound according to the invention.
[0124] In yet another preferred embodiment, an oligomeric compound
according to the invention or a composition according to the
invention is used in a hybridization reaction with a complementary
nucleic acid, e.g. the hybridization of an oligomeric compound
according to the invention to a plurality of oligonucleotides bound
to a solid phase at predetermined locations to form a microarray.
In even another preferred embodiment, an oligomeric compound
according to the invention is used as a primer, probe or capture
probe. The incorporation of compounds according to the invention
comprising six-membered rings into oligomeric compounds is
particularly useful for the stabilisation of an oligomeric compound
according to the invention against the digestion by nuclease and
depurination of purine bases.
[0125] In yet another preferred embodiment, an oligomeric compound
according to the invention is provided that is attached to a solid
phase and that is preferably a compound with Formula III. This is
particularly preferred for sequence-specific capturing of RNA as
hexitol nucleic acids primarily bind to RNA (Lescrinier, E., Chem.
Biol. 7 (2000) 719-731).
[0126] In another embodiment of the invention a method for the
detection of a target nucleic acid in a sample is provided
comprising the steps of [0127] (a) providing a sample suspected to
contain the target nucleic acid [0128] (b) providing an oligomeric
compound according to the invention, which is essentially
complementary to a part or all of the target nucleic acid, [0129]
(c) optionally amplifying the target nucleic acid with a
template-dependent DNA polymerase and primers [0130] (c) contacting
the sample with the oligomeric compound under conditions for
binding the oligomeric compound to the target nucleic acid, [0131]
(d) determining the binding product or the degree of hybridization
between the target nucleic acid and the oligomeric compound as a
measure of the presence, absence or amount of the target nucleic
acid.
[0132] Preferably in step (d) of the method, the degree of
hybridization is determined by the quantity of the first or second
fluorescent label that is released from the oligomeric compound
hybridized to the target nucleic acid by exonuclease hydrolysis by
the template-dependent DNA polymerase. Therefor, preferably, an
oligomeric compound according to the invention comprises two
labels, preferably two fluorescent labels.
[0133] The amplification is performed preferably with the
polymerase chain reaction which specifically amplifies target
nucleic acids to detectable amounts. Other possible amplification
reactions are the Ligase Chain Reaction (LCR; Wu, D. Y., and
Wallace, R. B., Genomics 4 (1989) 560-569; and Barany, F., Proc.
Natl. Acad. Sci. USA 88 (1991) 189-193); Polymerase Ligase Chain
Reaction (Barany, F., PCR Methods and Appl. 1 (1991) 5-16); Gap-LCR
(WO 90/01069); Repair Chain Reaction (EP 0439182), 3SR (Kwoh, D.
Y., et al., Proc. Natl. Acad. Sci. USA 86 (1989) 1173-1177;
Guatelli, J. C., et al., Proc. Natl. Acad. Sci. USA 87 (1990)
1874-1878; WO 02/08808), and NASBA (U.S. Pat. No. 5,130,238).
Further, there are strand displacement amplification (SDA),
transcription mediated amplification (TMA) and
Q.beta.-amplification (for a review see e.g. Whelen, A. C., and
Persing, D. H., Annu. Rev. Microbiol. 50 (1996) 349-373; Abramson,
R. D., and Myers, T. W., Current Opinion in Biotechnology 4 (1993)
41-47).
[0134] The preferred template-dependent DNA polymerase is Taq
polymerase.
[0135] In a preferred embodiment of the method for the detection of
a target nucleic acid, the format used in the TaqMan.RTM. assay is
contemplated whereby the oligomeric compound according to the
invention is used as a probe. Therefor, the oligomeric compound
according to the invention comprises a label as R.sup.7 which is
preferably a fluorescent label, preferably fluorescein. The
oligomeric compound according to the invention may further comprise
other fluorescent labels wherein the emission wavelengths of one of
the fluorescent labels overlap the absorption wavelengths of
another of the fluorescent labels. Preferably, the oligomeric
compound further comprises a second fluorescent label acting as a
quenching agent that quenches the fluorescence emission of the
fluorescent label, which can be fluorescein. Preferably the
quenching agent is a fluorescent rhodamine or cyanine. The
quenching agent can also be a non-fluorescent compound or dye as
dabcyl ("Dark Quencher"). The oligomeric compound according to the
invention cannot be extended enzymatically to be used as probe in
the TaqMan.RTM. format as principally set out in U.S. Pat. No.
5,210,015, U.S. Pat. No. 5,487,972 or U.S. Pat. No. 5,804,375.
Preferably, the monomeric unit at the 3'-end of the oligomeric
compound is a 2',3'-dideoxynucleotide or a 3'-phosphorylated
nucleotide. Preferably for use in the TaqMan.RTM. format, the
compound according to the invention with a label as well as a
second compound with the label may be located internally in the
modified oligonucleotide according to the invention or at the
5'-end and/or 3'-end of the modified oligonucleotide according to
the invention. Therefore, in a preferred embodiment of the
invention. In consequence for the format used in the TaqMan.RTM.
assay, in the determination step of the method, the spatial
relationship between the fluorescent label and the second label,
i.e. the quenching agent, subsequent to hybridization is altered,
preferably by exonuclease hydrolysis of a template-dependent DNA
polymerase, preferably the Taq-Polymerase, of the nucleic binding
compound whereby release of label occurs as a result of exonuclease
hydrolysis. The degree of hybridization between the oligomeric
compound according to the invention and the target nucleic acid is
determined by the quantity of label that is released from the
oligomeric compound according to the invention subsequent to
hybridization. Therefore it is a preferred embodiment of the
invention that in step (d) the degree of hybridization is
determined by the quantity of label that is released from the
oligomeric compound hybridized to the nucleic acid by exonuclease
hydrolysis by the template-dependent DNA polymerase.
[0136] In a very preferred embodiment of the invention related in
more detail to the TaqMan.RTM. assay format, a method for the
detection of a target nucleic acid in a sample is provided
comprising the steps of [0137] (a) contacting a sample comprising
single-stranded nucleic acids with an oligonucleotide containing a
sequence complementary to a region of the target nucleic acid and
an oligomeric compound according to the invention, whereby R.sup.7
is a fluorescent label and the oligomeric compound contains a
second fluorescent label, and whereby said oligomeric compound
contains a sequence complementary to a second region of the same
target nucleic acid sequence strand, but not including the nucleic
acid sequence defined by the oligonucleotide, to create a mixture
of duplexes during hybridization conditions, wherein the duplexes
comprise the target nucleic acid annealed to the oligonucleotide
and to the oligomeric compound such that the 3' end of the first
oligonucleotide is upstream of the 5' end of the oligomeric
compound. [0138] (b) maintaining the mixture of step (a) having a
5' to ' nuclease activity under conditions sufficient to permit the
5' to ' nuclease activity of the polymerase to leave the annealed,
oligomeric compound and release labeled fragments; and [0139] (c)
detecting and/or measuring the release of labeled fragments.
[0140] In another embodiment of the invention, a format for the use
in the LightCycler.RTM. instrument is provided as described in U.S.
Pat. No. 6,174,670. For use in the formats used in the
LightCycler.RTM. instrument, the compound according to the
invention will be preferably at the 3'- or 5'-end, i.e. the
monomeric unit at the 3'- or 5'-end of the oligomeric compound
after the synthesis thereof. These formats apply the fluorescent
resonance energy transfer (see, for example, U.S. Pat Nos.
4,996,143, 5,565,322, 5,849,489, and 6,162,603) and are based on
the fact that when a donor and a corresponding acceptor fluorescent
label are positioned within a certain distance of each other,
energy transfer takes place between the two fluorescent labels that
can be visualized or otherwise detected and/or quantitated. As used
herein, two probes, each containing a fluorescent label, whereby at
least one thereof is an oligomeric compound according to the
invention, can hybridize to an amplification product at particular
positions determined by the complementarity of the probes to the
target nucleic acid. The fluorescent label according to the
invention of the oligomeric compound according to the invention may
be a donor or acceptor fluorescent label. Upon hybridization of the
probes to the amplification product at the appropriate positions, a
FRET signal is generated. Fluorescent analysis can be carried out
using, for example, a photon counting epifluorescent microscope
system (containing the appropriate dichroic mirror and filters for
monitoring fluorescent emission at the particular range), a photon
counting photomultiplier system, or a fluorometer. Excitation to
initiate energy transfer can be carried out with an argon ion
laser, a high intensity mercury (Hg) arc lamp, a fiber optic light
source, or other high intensity light source appropriately filtered
for excitation in the desired range. As used herein with respect to
donor and corresponding acceptor fluorescent labels,
"corresponding" refers to an acceptor fluorescent label having an
excitation spectrum that overlaps the emission spectrum of the
donor fluorescent label. Accordingly, efficient non-radiative
energy transfer can be produced there between. The preferred
fluorescent label is fluorescein as the donor fluorescent label,
whereby the acceptor fluorescent label is rhodamine, however,
preferred is a cyanine dye, preferably Cy5 as described in U.S.
Pat. No. 6,174,670.
[0141] Therefore is an embodiment of the invention, a method for
detecting the presence or absence of a target nucleic acid in a
sample is provided comprising the steps of: [0142] (a) performing
at least one cycling step, wherein a cycling step comprises an
amplifying step and a hybridizing step, wherein said amplifying
step comprises contacting said sample with primers to produce an
amplification product if target nucleic acid is present in said
sample, wherein said hybridizing step comprises contacting said
sample with a pair of probes, wherein the members of said pair of
probes hybridize to said amplification product within no more than
five nucleotides of each other, wherein a first probe of said pair
of probes is labeled with a donor fluorescent label and wherein a
second probe of said pair of probes is labeled with a corresponding
acceptor fluorescent label, and whereby one of the probes is an
oligomeric compound according to the invention, and [0143] (b)
detecting the presence of absence of fluorescence resonance energy
transfer between said donor fluorescent label of said first probe
and said acceptor fluorescent label of said second probe, wherein
the presence of FRET is indicative of the presence of the target
nucleic acid in the sample, and wherein the absence of FRET is
indicative of the absence of the target nucleic acid in the
sample.
[0144] Therefore, in a preferred embodiment of the invention, a
method for detecting a target nucleic acid in a sample is provided,
comprising the steps of amplifying the nucleic acid by polymerase
chain reaction in the presence of two nucleic acid probes, whereby
a probe is an oligomeric compound according to the invention, that
hybridize to adjacent regions of the target nucleic acid, one of
said probes being labeled with an acceptor fluorescent label and
the other probe labeled with a donor fluorescent label of a
fluorescence energy transfer pair such that upon hybridization of
the two probes with the target nucleic acid, the donor and acceptor
fluorescent labels are within 25 nucleotides of one another, said
polymerase chain reaction comprising the steps of adding a
thermostable polymerase, nucleotides and primers for the target
nucleic acid to the sample and thermally cycling the sample between
at least a denaturation temperature and an elongation temperature;
exciting the biological sample with light at a wavelength absorbed
by the donor fluorescent label and detecting fluorescent emission
from the fluorescent energy transfer pair.
[0145] In another preferred embodiment of the invention, a method
for the detection of a target nucleic acid in sample is provided
comprising the steps of amplifying the nucleic acid by polymerase
chain reaction in the presence of two nucleic acid probes, whereby
a probe is an oligomeric compound according to the invention, that
hybridize to adjacent regions of the target nucleic acid, one of
said probes being labeled with an acceptor fluorescent label and
the other probe labeled with donor fluorescent label of a
fluorescence energy transfer pair such that upon hybridization of
the two probes with the target nucleic acid, the donor and acceptor
fluorescent labels are within 25 nucleotides of one another, said
polymerase chain reaction comprising the steps of adding a
thermostable polymerase, nucleotides and primers for the target
nucleic acid to the sample and thermally cycling the sample between
at least a denaturation temperature and an elongation temperature;
exciting the sample with light at a wavelength absorbed by the
donor label and monitoring temperature dependent fluorescence from
the fluorescent energy transfer pair.
[0146] In another preferred embodiment of the invention, a method
for determining the presence or the amount of a target nucleic acid
in a sample comprising the steps of [0147] (a) providing a target
nucleic acid from a sample to be analyzed. [0148] (b) synthesizing
double stranded complementary DNA from the target nucleic acid.
[0149] (c) amplifying the target nucleic acid in the presence of a
compound according to the invention and nucleoside triphosphates
whereby a labelled nucleic acid is obtained. [0150] (d) hybridizing
the labelled target nucleic acid to an array of oligomeric
compounds at a defined location, and [0151] (e) measuring the
fluorescence intensities at each defined location whereby the
presence or the amount of the target nucleic acid is
determined.
[0152] This is the method which is used for the detection of target
nucleic acids using the array format. Preferably, the method
described in U.S. Pat. Nos. 5,545,522; 5,716,785; U.S. Pat. No.
5,891,636; U.S. Pat. No. 6,291.170 is used in steps b) and c) of
the method according to the invention whereby double stranded cDNA
is synthesized with a primer comprising the bacterial T7-Promoter
and labeled RNA is transcribed in the presence of ribonucleoside
triphosphates whereby labels are attached to some of the nucleoside
triphosphates. The target nucleic acid in this case is preferably
ribonucleic acid.
[0153] In another preferred embodiment a kit of parts is
contemplated by the invention whereby the kit contains a
template-dependent polymerase, preferably having 5' to 3'
exonucleolytic activity, preferably the Taq Polymerase, a set of
primers, nucleotides and a oligomeric compound according to the
invention, preferably wherein R.sup.7 is a label. Such kits known
in the art further comprise plastics ware which can be used during
the amplification procedure as e.g. microtiter plates in the 96 or
384 well format or just ordinary reaction tubes manufactured e.g.
by Eppendorf, Hamburg, Germany and all other reagents for carrying
out the method according to the invention.
[0154] In another preferred embodiment, a kit of parts is provided
containing a compound according to the invention which is a
triphosphate and can be enzymatically incorporated into nucleic
acids. The kit further comprises nucleoside triphosphates and a
polymerase, which may be e.g. ribonucleoside triphosphates and a
RNA polymerase.
[0155] In another embodiment of the invention, the kit contains
reagents for isolating the nucleic acid. Therefore, the kit can
additionally contain a material with an affinity to nucleic acids,
preferably the material with an affinity to nucleic acids comprises
a material with a silica surface. Preferably, the material with a
silica surface is a glass. Most preferably, the material with an
affinity to nucleic acids is a composition comprising magnetic
glass particles as described in WO 96/41811 or WO 01/37291. The kit
can further or additionally comprise a lysis buffer containing e.g.
chaotropic agents, detergents or alcohols or mixtures thereof which
allow the lysis of cells and separately a protease, e.g. proteinase
K, for the digestion of unwanted proteins. These components of the
kit according to the invention may be provided separately in tubes
or storage containers. Depending on the nature of the components,
these may be even provided in a single tube or storage container.
The kit may further or additionally comprise a washing solution
which is suitable for the washing step of the magnetic glass
particles when DNA or RNA is bound thereto. This washing solution
may contain ethanol and/or chaotropic agents in a buffered solution
or solutions with an acidic pH without ethanol and/or chaotropic
agents as described above. Often the washing solution or other
solutions are provided as stock solutions which have to be diluted
before use. The kit may further or additionally comprise an eluent
or elution buffer, i.e. a solution or a buffer (e.g. 10 mM Tris, 1
mM EDTA, pH 8.0) or pure water to elute the DNA or RNA bound to the
magnetic glass particles. Further, additional reagents or buffered
solutions may be present which can be used for the purification of
a nucleic acid, i.e. DNA or RNA.
[0156] The following examples, references and figures are provided
to aid the understanding of the present invention, the true scope
of which is set forth in the appended claims. It is understood that
modifications can be made in the procedures set forth without
departing from the spirit of the invention.
EXAMPLES
Preparative Example: Synthesis of A Phosphoramidite
N-Fmoc-N'-acrylyl-1,6-diaminohexane
[0157] To 1.26 g (3 mmol) of Fmoc diaminohexane (Bachem Q 2045) in
90 ml of abs. chloroform were added 1.70 ml (12 mmol) of
triethylamine. The mixture was cooled to 0.degree. C. and 300 .mu.l
(3.6 mmol) of acrylic acid chloride were added dropwise. The
mixture was allowed to warm to room temperature and was stirred
overnight. The suspension was filtered and the filtrate was
evaporated at an rotary evaporator. The remainder was purified by
column chromatography on silica gel with chloroform/methanol 4:1 as
eluent (TLC control on silica gel chloroform/methanol 4:1 RF=0.75).
Fractions containing the product were collected and evaporated to
dryness. Yield: 440 mg.
1,5-Anhydro-2-(5-(6-fluoren-9-ylmethoxycarbonylamino-hexylcarbamoyl)-vinyl-
)-uracil-1yl)-2,3-dideoxy-D-arabino-hexitol
[0158] 5.8 mg (0.023 mmol) of palladium acetate (Aldrich 20.586-9),
13 mg (0.05 mmol) of triphenylphosphine (Merck 808270) and 86 .mu.l
(0.61 mmol) of triethylamine were refluxed in 16 ml of abs. dioxane
for 15 min. Then 392 mg (1 mmol) of
N-Fmoc-N'-acrylyl-1,6-diaminohexane and 180 mg (0.47 mmol) of
1,5-anhydro-2,3-dideoxy-2-(5-iodouracil-1-yl)-D-arabino-hexitol
(Verheggen, I. et al J. Med. Chem. 38 (1995) 826-835) were added
and the mixture was heated for 3 h at 80.degree. C. The mixture was
allowed to cool to room temperature and was filtrated. The filtrate
was evaporated to dryness by using an rotary evaporator. The
remainder was purified by column chromatography on silica gel with
chloroform/methanol 5:1 as eluent. (TLC silica gel:
chloroform/methanol 4:1 RF=0.47).
[0159] Fractions containing the product were collected and
evaporated to dryness using an rotary evaporator. Yield: 210
mg.
6-O-(4,4'-Dimethoxytrityl)-1,5-anhydro-2-(5-(6-fluoren-9-ylmethoxycarbonyl-
-amino-hexylcarbamoyl)-vinyl)uracil-1yl)-2,3-dideoxy-D-arabino-hexitol
[0160] 220 mg (0.32 mmol) of
1,5-Anhydro-2-(5-(6-fluoren-9-ylmethoxy-carbonyl-amino-hexylcarbamoyl)-vi-
nyl)uracil-1yl)-2,3-dideoxy-D-arabino-hexitol were coevaporated
with 3.times.5 ml of abs. pyridine and then dissolved in 5 ml of
abd. pyridine. Thereafter, 140 mg (0.39 mmol) of
4,4'-dimethoxytritylchloride in 5 ml of pyridine are added at room
temperature within 15 min under stirring. The reaction mixture was
stirred for another 2 h at room temperature. Then pyridine was
evaporated and the residue was dissolved in 50 ml of ethyl acetate
and washed twice with 50 ml of 0.1 M sodium phosphate buffer pH 7.5
Organic layer was separated, dried over sodium sulfate, filtered
and evaporated to dryness. The residue was purified by
flash-chromatography over silica gel (n-hexane/ethyl acetate/1%
triethylamine gradient). Product fractions were combined,
evaporated and dried at high vacuum. Yield: 235 mg.
6-O-(4,4'-Dimethoxytrityl)-1,5-anhydro-2-(5-(6-fluoren-9-ylmethoxycarbonyl-
-amino-hexylcarbamoyl)-vinyl)uracil-1yl)-2,3-dideoxy-D-arabino-hexitol-4-O-
-[N,N-diisopropyl-(2-cyanoethyl)]-phosphoramidite
[0161] 200 mg (0.21 mmol) of
6-O-(4,4'-Dimethoxytrityl)-1,5-anhydro-2-(5-(6-fluoren-9-ylmethoxycarbony-
l-amino-hexylcarbamoyl)-vinyl)uracil-1yl)-2,3-dideoxy-D-arabino-hexitol
were dissolved in 5 ml of dichloromethane under Ar-atmosphere.
thereafter 68 .mu.l (0.38 mmol) of N-ethyldiisopropylamine, and
within 15 min 72 mg (0.28 mmol) of
chloro-2-cyanoethyhoxy-diisopropylamino-phosphane in 5 ml of
dichloromethane were added. The reaction mixture was stirred for 1
h at room temperature. The 10 ml of dichloromethane were added.
Reaction mixture was washed twice with 20 ml of 0.1 M sodium
phophate buffer pH 7.5. Organic layer was separated, dried over
sodium sulfate, filtered and evaporated to dryness. The residue was
purified by flash-chromatography over silica gel (n-hexane/acetone
gradient). Product fractions were combined, evaporated and dried at
high vacuum. Yield: 170 mg.
Preparative Example: Synthesis of Triphosphate
1,5-Anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-hexitol 6
monophosphate dilithium salt
[0162] 127 mg (0.48 mmol) of
1,5-Anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-hexitol
(Verheggen, I. et al., J. Med. Chem. 36 (1993) 2033-2040) were
dissolved in 12 ml Triethylphosphate and 260 .mu. diisopropyl ethyl
amine were added. The flask was cooled in an ice bath to
0-4.degree. C. 36 .mu.l Phosphoroxychloride were added. After
stirring for 10 min at 0-4.degree. C. Triethylamin/acetic acid
buffer 0.1 M pH 8.5 was added. The solvents were evaporated at 0.1
mbar at 40.degree. C. using a rotary evaporator. The residue was
dissolved in 20 ml water and purified by ion exchange on DEAE
Sephadex A 25 Cl: Buffer A water, Buffer B 0.5 M LiCl, gradient in
60 min to 100% B monitoring by UV/VIS detector at 260 nm. The
corresponding fractions were collected and evaporated at reduced
pressure to a volume of 1-3 ml. The product solution was added to a
200 ml of a 2:1 mixture of Acetone/Ethanol. The suspension was
centrifuged, the resulting pellet was washed 3 times with acetone
to remove LiCl and then dried in high vacuum. yield 120 mg.
1,5 Anhydro-2-(6-(1,2,4-triazol-4-yl)-purin-9-yl)
)-2,3-dideoxy-D-arabino-hexitol-6-monophosphate (Method Described
In Miles, W. M., et al., J. Am. Chem. Soc. 117 (1995)
5951-5957)
[0163] 5 ml dried pyridine was added to 120 mg (0.34 mmol) of b
1,5-Anhydro-2-(6-(1,2,4-triazol-4-yl)-purin-9-yl)
)-2,3-dideoxy-D-arabino-hexitol-6-monophosphate dilithium salt and
250 mg (1.2 mmol) 1,2-bis[(dimethylamino)methylene)]hydrazine and
the mixture was evaporated.
[0164] 2 ml Puridine and 173 .mu.l (1.36 mmol) mmol)
Trimethylsilylchloride were added, the mixture was heated at
100.degree. C. for 24 h. The solvent were evaporated in vacuum the
residue was dissolved in water and purified by ion exchange
chromatography on DEAE Sephadex A 25 Cl: Buffer A water, Buffer B
0.5 M LiCl, gradient in 60 min to 100% B monitoring by UV/VIS
detector at 260 nm. The corresponding fractions were collected and
evaporated at reduced pressure. The remainder was directly used for
the next synthetic step without removing excess lithium
chloride.
N6(6-aminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-hexitol-6-m-
onophosphate triethylammonium salt
[0165] The remainder of step II (1,5
Anhydro-2-(6-(1,2,4-triazol-4-yl)-purin-9-yl)
)-2,3-dideoxy-D-arabino-hexitol-6-monophosphate) was dissolved in
20 water filtrated and reacted with 1 ml diaminohexane for 15 h at
80.degree. C. The mixture was evaporated at reduced pressure. The
residue was dissolved in 5 ml 0.1 M Triethylammonium bicarbonate
pH=8 and purified by ion exchange chromatography on DEAE Sephadex A
25 using a gradient form 0.1 m to 0.3 Triethylammonium bicarbonate
monitoring at 260 nm. Appropriate fractions (color development with
Ninhydrin on TLC) were collected and evaporated under vacuum. The
residue was diluted in water and evaporated again under vacuum.
This process was repeated for three times. Yield 80 mg.
N6(6-trifluoracetaminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-
-hexitol-6-monophosphate
[0166] 80 mg (0.12 mmol)
N6(6-aminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-hexitol-6--
monophosphate bis triethylammonium salt was dissolved in 10 ml
water 10 ml S-ethyltrifluorothiooacetate was added and the pH was
adjusted to 10 with 5 K Lithiumhydroxide. The mixture was stirred
for 4 h at room temperature. The mixture was diluted with 25 ml 0.1
M Triethylammonium bicarbonate pH=8 The solution was loaded on to a
DEAE Sephadex Column and eluted with a gradient from 0.1-0.4 M
Triethylammoniumbicarbonate pH 8 monitoring at 260 nm. The
fractions containing the trifluoracetylated product were collected
and evaporated under vacuum. Excess Triethylammoniumbicarbonate was
removed by several coevaporations with water. Yield 82 mg
N6(6-trifluoracetaminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D-arabino-
-hexitol-6-triphosphate
[0167] 82 mg (0.11 mmol)
N6(6-trifluoroacetaminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D
arabino-hexitol-6-monophosphate bis triethylammonium salt was
dissolved in 3 ml water dry DMF 89 mg (0.55 mmol)
Carbonyldiimidazol were added the mixture was stirred for 2 h at
RT. 0.5 ml Methanol were added and the mixture stirred for 20 min
at RT. Methanol was removed by evaporation under reduced pressure.
Then 0.7 ml of a 0.8 M solution of bis triethylammonium
pyrophosphate in DMF (0.55 mmol) was added. The mixture was stirred
overnight at room temperature. The solvents were evaporated at 0.1
mbar at 40.degree. C. by using a rotary evaporator. The residue was
dissolved in 5 ml 0.1 M Triethylammoniumbicarbonate pH-8 The The
solution was loaded on to a DEAE Sephadex Column and eluted with a
gradient from 0.1-1 M Triethylammoniumbicarbonate pH 8 monitoring
at 260 nm. The fractions containing the triphosphate were collected
and evaporated under vacuum. Excess triethylammoniumbicarbonate was
removed by several coevaporations with water. Yield 69 mg
N6(6-aminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D
arabino-hexitol-6-triphosphate
[0168] 69 mg (0.06 mmol)
N6(6-trifluoroacetaminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D
arabino-hexitol-6-triphosphate was dissolved in 4 ml water was
added and the pH adjusted to 11.5 with 6M NaOH The mixture was
stirred for 4 h at room temperature. The pH was then adjusted to pH
8 with 2M HCl and 10 of 0.1 Triethylammoniumbicarbonate pH=8 were
added. The solution was loaded on to a DEAE Sephadex Column and
eluted with a gradient from 0.1-1.0 M Triethylammoniumbicarbonate
pH 8 monitoring at 260 nm. The fractions containing the
triphosphate were collected and evaporated under vacuum. The
presence of the amino group was verified by ninhydrine reaction
Excess triethylammonium-bicarbonate was removed by several
coevaporations with water. Yield 40 mg
N6(6-(6-biotinamido-hexanoate)-amidohexyl)-anhydro-9H
(adenin-9-yl)-2,3-dideoxy-D arabino-hexitol-6-triphosphate
[0169] 40 mg (0.03 mmol)
N6(6-aminohexyl)-anhydro-2-(adenin-9-yl)-2,3-dideoxy-D
arabino-hexitol-6-triphosphate tetra triethylammonium salt was
dissolved in 250 .mu.l 0.1 M sodium borate water pH 8.5 A solution
of 25 mg (0.055 mmol) biotin hexancarbonsaure NHS ester (Sigma
ordering number B2643) in 800 .mu.l amine free DMF was added. the
mixture was stirred overnight at room temperature. The solution was
evaporated under vacuum. The remainder was dissolved in 5 ml 0.1 M
triethylammoniumbicarbonate pH=8 The solution was loaded on to a
DEAE Sephadex column and eluted with a gradient from 0.2-1.2 M
Triethylammoniumbicarbonate pH 8 monitoring at 260 nm. The
fractions containing the biotinylated triphosphate were collected
and evaporated under vacuum. Excess triethylammonium-bicarbonate
was removed by several coevaporations with water. Yield 15 mg NMR
(Bruker DPX 300, Solvent D.sub.2O .sup.1H [ppm]: 1.10-1.85 (m)
[22H], 2.18 (m) [4 H], 2.45 (d broad) [1H], 2.65 (d) [1H], 2.85
(dd) [1H], 3.08 (m)[4H], 3.56 (s, broad) [2H], 3.61 (m) [2H], 3.79
(m) [1H], 4.08 (d) [1H], 4.28 (m) [4H], 4.50 (dd) [1H], 8.20 (s)
[1H], 8.42 (s) [1H], .sup.31P [ppm]: -21.77 (t); 10.08 (d); 9.50
(d)
N6(6-(6-biotinamido-hexanoate)
amidohexyl)-9-[1R,3S,4R)-3-hydroxy-4->-(tetrahydroxy-[1]triphosphoryl
oxymethyl) cyclohexenyl]adenine tetraethylammonium salt
(adenin-9-yl)-2,3-dideoxy-D arabino-hexitol-6-triphosphate
[0170] This compound was synthesized from 9-
[1R,3S,4R)-3-Hydroxy-4-hydroxymethylcyclohexenyl]adenine (Wang J.,
Herdewijn P., J. Org. Chem. 64 (1999) 7820-7827.) by using the same
synthesis pathway as described above.
[0171] NMR (Bruker DPX 300, Solvent D.sub.2O .sup.1H [ppm]: 1.22
)t) [36H], 1.30-1.82 (m) [18H], 2.18 (m) [64 H], 2.51 (s, broad)
[1H], 2.68 (d) [1H], 2.86 (dd) [1H], 3.28 (q) [24H], 3.56 (s,
broad) [2H], 3.90 (q) [1H], 3.79 (m) [1H], 4.18 (m) [2H], 4.28 (m)
[1H], 4.50 (dd) [1H], 5.98 (dt) [1H], 6.21 (d) [1H], 8.13 (s) [1H],
8.21 (s) [1H], .sup.31P [ppm]: -22.04 (t); -9.72 (d); 9.53 (d)
1,5-Anhydro-2-(uracil-1yl)-2,3-dideoxy-D-arabino-hexitol 6
triphosphate
[0172] 200 mg (0.82 mmol)
1,5-Anhydro-2-(uracil-1yl)-2,3-dideoxy-D-arabino-hexitol
(Verheggen, I., et al., J. Med. Chem. 38 (1995) 826-835) was
converted to 150 mg (0.44 mmol) monophosphate according to the
procedure described above. The monophosphate was converted to the
triphosphate according to the procedure described in Moffat, J. G.,
Khorana, H. G. J. Am. Chem. Soc. 1961, 83, 649-658. Therefore 150
mg (0.44 mmol) of
1,5-Anhydro-2-(uracil-1yl)-2,3-dideoxy-D-arabino-hexitol 6
monophosphate dilithium salt was converted in the free acid by
passing through a Dowex H form 50X8-100 column) It was eluted with
water and the UV absorbing fractions were collected and
concentrated to 2 ml. 2 ml of tert butyl alcohol was added and the
mixture was transferred in a two neck flack fitted with a reflux
condenser and a rubber septum. 0.3 ml (3 mmol) morpholine were
added using a syringe needle. The mixture was heated to reflux and
a solution of 0.6 mg (2.9 mmol) dicyclohexylcarbondiimide in 3 ml
tert butyl alcohol was added dropwise over a period of 2 h. The
mixture was refluxed for 15 h. The mixture was cooled to room
temperature and filtrated. The filtrate was concentrated to 2 ml
and the concentrate was extracted three times with diethyl ether.
The aqueous layer was evaporated to dryness in vacuum. The residue
was dissolved in 5 DMF and added to a solution of 2.8 ml of a 0.8 M
solution of bis tri-n-butylammonium pyrophosphate in DMF (2.2
mmol). The mixture was stirred overnight under Argon at room
temperature. The solvents were evaporated at reduced pressure at
40.degree. C. by using a rotary evaporator. The residue was
dissolved in 5 ml water. The solution was loaded on to a DEAE The
fractions
[0173] Incorporation rates of biotinylated hUTP, hATP and CeATP
(see FIG. 4) which are considered to be 2' deoxy-NTP analogs were
compared with the standard biotin-16-dUTP via a dot blot dilution
series of cDNAs labeled using AMV reverse transcriptase. Firstly,
we investigated the influence of different ratios biotin hUTP:dUTP
based on a dot blot dilution series (detection with SA-AP/CPD*). We
found that a 1:4 ratio (-20%) is sufficient for labeling. Using
this ratio different analogs were compared with biotin dUTP.
Incorporation efficiency increases in the row biotin hATP<biotin
hUTP-biotin dCeATP<biotin dUTP (see FIG. 5a-c)
[0174] Another analog we studied was aUTP which has an additional
hydroxyl group and therefore is similar to a ribonucleotide. We
investigated incorporation of biotin aUTP with different RNA
polymerases. T7 RNA polymerase is the best choice for incorporation
of biotin aUTP. However, incorporation yield is by a factor of
approx. 25 times lower compared to biotin UTP (see FIG. 6).
Microarray-Based Expression Profiling Experiment
[0175] The performance of Bio-h-UTP was tested in a microarray
based expression-profiling experiment. This application enables
researcher to monitor mRNA levels of many genes in parallel. For
this purpose oligonucleotides were covalently attached to a solid
surface (i.e. glass slide) in an ordered fashion. In the next step
this array of oligonucleotides is hybridized with a pool of target
molecules derived from a defined sample (i.e. tissue, cell line,
etc.). For target synthesis total RNA has to be isolated from the
sample. Afterwards mRNA is primed with an oligo dT primer followed
by an enzymatically cDNA synthesis using reverse transcriptase.
During this step Biotin labeled nucleotides are inserted into the
cDNA strand. For hybridization cDNA is purified and applied onto
the array. Incubation was carried out over-night followed by a
stringent wash procedure. After washing of the array incubation
with a fluorophore labeled streptavidine conjugate was performed.
For signal detection, glass slides were scanned with a convocal
laser scan microscope in order to quantify the amount of hybridized
target molecules. By utilizing computational analysis signal
intensities were correlate to the distinct oligonucleotide
representing a specific gene.
Experimental Procedure In Detail
[0176] Glass arrays were ordered containing oligonucleotides
specific for distinct rat genes (rat oligo test set) in triplicate
(MWG-Biotech AG, Ebersberg, Germany). RNA isolation was performed
by utilizing the RNeasy Kit (QIAGEN, Hilden, Germany) according to
the kit manual. One hundred micro gram of total mouse RNA derived
from liver isolated from a liver tissue sample served as template
for target preparation using a cDNA synthesis kit (Roche, Mannheim,
Germany), including incorporation of labeled Bio-h-dUTP. Labeling
procedure: 100 .mu.g of total RNA was incubated 10 minutes at
70.degree. C. in 18 .mu.l H.sub.2O with 2 .mu.g of a oligo dT 24mer
and chilled on ice. Reaction mix containing: 5 .mu.l RT-buffer, 4
.mu.l DTT, 4 .mu.l dNTP (5 mM a, g, c and 3 mM T), 0.4 .mu.l
Bio-h-dUTP, 1.8 .mu.l AMV reverse Transcriptase, 0.2 .mu.l RNAsin,
3.5 .mu.l H.sub.2O was added and incubated for 1 hour at 42.degree.
C. The labeling reaction was terminated by adding 10 .mu.l of 1N
NaOH followed by a 10 minute incubation at 65.degree. C.
[0177] Solution was neutralized with 10 .mu.l of 1N HCl and 22
.mu.l of 1M TrisHCl (pH=7.5). The purification of the labeled
target was performed with HighPure spin columns (Roche, Mannheim,
Germany) according to instruction manual.
[0178] Hybridization of the arrays was performed for 16 hours in a
humidity chamber according to the instructions of the glass array
manufacturer.
[0179] After hybridization the array was washed three times for 5
minutes at 30.degree. C. in 2.times.SSC+1% SDS, 1.times.SSC and
0.5.times.SSC respectively.
[0180] Antibody detection was performed by preblocking for 30
minutes in 2.times.SSC and 1% caseine as well as incubation for 10
minutes with streptavidine-Cy3 (1 .mu.g/ml) in 2.times.SSC+1%
caseine. Final washing was performed two times for 5 minutes in
2.times.SSC+0.2% SDS as well as one time for 5 minutes in
2.times.SSC.
[0181] For signal detection the array was scanned with a confocal
laser scanner (Axon, Union City, USA) with a PMT setting as well as
a gain of 80. Image analysis was performed with Imagene software
(BioDiscovery, Marina del Rey, USA).
Results
[0182] As expected control spots containing probe sequences
matching with none of the target sequences revealed no signal and
therefore ensure specificity within the hybridization procedure.
Also spots corresponding to genes not known to be expressed in
liver revealed low or no signal. On the other hand genes expressed
in wide range of tissues as well as genes specific for liver were
clearly detected demonstrating the good performance of Bio-h-dUTP
in this approach (see FIG. 7).
* * * * *