Method of determining the presence and quantifying the number of di- and trinucleotide repeats
First Claim
1. A method of quantifying the number of trinucleotide repeats in a nucleic acid of interest, comprising the steps of:
- (a) if the nucleic acid of interest is double stranded, treating the nucleic acid of interest to obtain unpaired nucleotide bases spanning the trinucleotide repeats and their flanking regions, or, if the nucleic acid of interest is single stranded, directly employing step (b);
(b) contacting the unpaired nucleotide bases spanning the number of trinucleotide repeats and their flanking regions with an oligonucleotide primer for hybridizing with a stretch of nucleotide bases present in the nucleic acid of interest partially or fully 3'"'"' of the nucleotide repeats to be quantified, so as to form a duplex between the primer and the nucleic acid of interest;
(c) providing means for confining the nucleic acid of interest and the oligonucleotide primer to a reaction chamber at all further steps (d) through (k); and
further comprising the cycled steps of;
(d) contacting the template primer duplex with a first primer extension unit for base pairing with one of the nucleotide bases, in the core sequence of the trinucleotide repeats, and with a template dependent extension enzyme;
(e) eliminating non-incorporated units of said first primer extension units;
(f) contacting the template primer duplex, which primer is now extended by one unit as described in step (d), with a second primer extension unit for base pairing with a second nucleotide base, in the core sequence of the repeat, said second nucleotide base being located adjacent to and immediately 5'"'"' of the nucleotide base employed under step (d), and with a template dependent extension enzyme;
(g) eliminating non-incorporated units of said second primer extension units;
(h) contacting the template primer duplex, which primer is now elongated by one further additional unit as described in step (f), with;
(i) a third primer extension unit for base pairing with a third nucleotide base, in the core sequence of the repeat, said third nucleotide base being located adjacent to and immediately 5'"'"' of the nucleotide base under step (f);
(ii) a detection moiety which is conjugated with a fourth primer extension unit for base pairing with a nucleotide base 5'"'"' of the repeats, said nucleotide base being the first nucleotide base of a type not included among the nucleotide bases in the core sequence of the trinucleotide repeats, said detection moiety which is conjugated with said fourth primer extension unit may be present in selected cycles of this stage; and
(iii) a template dependent extension enzyme;
(i) eliminating non-incorporated units of said third and fourth primer extension units;
(j) if step (h) included said detection moiety which is conjugated with said fourth primer extension unit, detecting the presence of said detection moiety; and
if no detection is obtained,(k) repeating steps (d) to (j) until said detection moiety is detected, said detection of said detection moiety being indicative of the number of trinucleotide repeats included in the nucleic acid of interest.
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Abstract
A method aimed at the quantification of di- and trinucleotide repeat which includes (a) treating a sample containing the nucleic acids of interest to obtain unpaired nucleotide bases spanning the position of the repeats and flanking regions, if the nucleic acids are not already single stranded; (b) contacting the unpaired nucleotide bases with an oligonucleotide primer capable of hybridizing with a stretch of nucleotide bases present in the nucleic acid of interest preferably 3'"'"' of the trinucleotide repeats to be quantified, so as to form a duplex between the primer and the nucleic acid of interest; (c) providing means to ensure that the examined nucleic acid and the oligonucleotide primer are confined to a reaction chamber at all further steps; (d) contacting the duplex with a primer extension unit which is capable of base pairing with the first nucleotide base in the core sequence of the repeats, and a template dependent extension enzyme; (e) eliminating non-incorporated primer extension units; (f) contacting the template primer duplex with a primer extension unit which is capable of base pairing with the second nucleotide base in the core sequence of the repeats, and a template dependent extension enzyme; (g) eliminating non-incorporated primer extension units; (h) contacting the template primer hybrid with a primer extension unit which is capable of base pairing with the third nucleotide base in the core sequence of the repeats; a detection moiety containing, primer extension unit which is capable of base pairing with a nucleotide base 5'"'"' of the repeats region, said nucleotide base being the first nucleotide base of a type not included among the nucleotide bases in the core sequence of the trinucleotide repeats; and a template dependent extension enzyme; (i) eliminating non-incorporated primer extension units; (j) detecting for the presence of detection moiety containing primer extension unit; (k) steps (d) to (j) are repeated until detecting said detection moiety; (l) the number of repeats as stated under (k) enables the determination of the number of trinucleotide repeats, therefore enabling determination of the exact repetition number.
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Citations
45 Claims
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1. A method of quantifying the number of trinucleotide repeats in a nucleic acid of interest, comprising the steps of:
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(a) if the nucleic acid of interest is double stranded, treating the nucleic acid of interest to obtain unpaired nucleotide bases spanning the trinucleotide repeats and their flanking regions, or, if the nucleic acid of interest is single stranded, directly employing step (b); (b) contacting the unpaired nucleotide bases spanning the number of trinucleotide repeats and their flanking regions with an oligonucleotide primer for hybridizing with a stretch of nucleotide bases present in the nucleic acid of interest partially or fully 3'"'"' of the nucleotide repeats to be quantified, so as to form a duplex between the primer and the nucleic acid of interest; (c) providing means for confining the nucleic acid of interest and the oligonucleotide primer to a reaction chamber at all further steps (d) through (k); and further comprising the cycled steps of; (d) contacting the template primer duplex with a first primer extension unit for base pairing with one of the nucleotide bases, in the core sequence of the trinucleotide repeats, and with a template dependent extension enzyme; (e) eliminating non-incorporated units of said first primer extension units; (f) contacting the template primer duplex, which primer is now extended by one unit as described in step (d), with a second primer extension unit for base pairing with a second nucleotide base, in the core sequence of the repeat, said second nucleotide base being located adjacent to and immediately 5'"'"' of the nucleotide base employed under step (d), and with a template dependent extension enzyme; (g) eliminating non-incorporated units of said second primer extension units; (h) contacting the template primer duplex, which primer is now elongated by one further additional unit as described in step (f), with; (i) a third primer extension unit for base pairing with a third nucleotide base, in the core sequence of the repeat, said third nucleotide base being located adjacent to and immediately 5'"'"' of the nucleotide base under step (f); (ii) a detection moiety which is conjugated with a fourth primer extension unit for base pairing with a nucleotide base 5'"'"' of the repeats, said nucleotide base being the first nucleotide base of a type not included among the nucleotide bases in the core sequence of the trinucleotide repeats, said detection moiety which is conjugated with said fourth primer extension unit may be present in selected cycles of this stage; and (iii) a template dependent extension enzyme; (i) eliminating non-incorporated units of said third and fourth primer extension units; (j) if step (h) included said detection moiety which is conjugated with said fourth primer extension unit, detecting the presence of said detection moiety; and
if no detection is obtained,(k) repeating steps (d) to (j) until said detection moiety is detected, said detection of said detection moiety being indicative of the number of trinucleotide repeats included in the nucleic acid of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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34. A method of quantifying the number of dinucleotide repeats in a nucleic acid of interest, comprising the steps of:
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(a) if the nucleic acid of interest is double stranded, treating the nucleic acid of interest to obtain unpaired nucleotide bases spanning the dinucleotide repeats and their flanking regions, or, if the nucleic acid of interest is single stranded, directly employing step (b); (b) contacting the unpaired nucleotide bases spanning the number of dinucleotide repeats and their flanking regions with an oligonucleotide primer for hybridizing with a stretch of nucleotide bases present in the nucleic acid of interest partially or fully 3'"'"' of the nucleotide repeats to be quantified, so as to form a duplex between the primer and the nucleic acid of interest; (c) providing means for confining the nucleic acid of interest and the oligonucleotide primer to a reaction chamber at all further steps (d)-(i); and further comprising the cycled steps of; (d) contacting the template primer duplex with a first primer extension unit for base pairing with one of the nucleotide bases, in the core sequence of the dinucleotide repeats, and with a template dependent extension enzyme; (e) eliminating non-incorporated units of said first primer extension units; (f) contacting the template primer duplex, which primer is now extended by one unit as described in step (d), with; (i) a second primer extension unit for base pairing with a second nucleotide base, in the core sequence of the repeat, said second nucleotide base being located adjacent to and immediately 5'"'"' of the nucleotide base under step (d); (ii) a detection moiety which is conjugated with a third primer extension unit for base pairing with a nucleotide base 5'"'"' of the repeats, said nucleotide base being the first nucleotide base of a type not included among the nucleotide bases in the core sequence of the dinucleotide repeats, said detection moiety which is conjugated with said third primer extension unit may be present in selected cycles of this stage; and (iii) a template dependent extension enzyme; (g) eliminating non-incorporated units of said second and third primer extension units; (h) if step (f) included said detection moiety which is conjugated with said third primer extension unit, detecting the presence of said detection moiety; and
if no detection is obtained,(i) repeating steps (d) to (h) until said detection moiety is detected, said detection of said detection moiety being indicative of the number of dinucleotide repeats included in the nucleic acid of interest.
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Specification