Patent ID: 7553643

Claim:
A method of amplifying a target nucleic acid sequence in a sample comprising: a) contacting the sample with at least one forward primer and at least one reverse primer, an AP endonuclease, and a nucleic acid polymerase, under conditions sufficient to allow the forward and reverse primers to hybridize to the target nucleic acid and form a reaction mixture, wherein the forward and the reverse primer independently comprise a sequence structure (NA 1 -L) m -NA 2 , wherein NA 1 and NA 2 are nucleic acid sequences complementary to the target nucleic acid,L is an AP endonuclease-cleavable linker incorporated at a predetermined specific site, and m is from 0 to 100, wherein at least one of said forward and reverse primer comprises an AP endonuclease-cleavable linker L, wherein the primer comprising the AP endonuclease-cleavable linker is extendable and the sequence structure (NA 1 -L) m -NA 2 comprises nucleotides having at least one modified base independently selected from the group consisting of 6-amino-3-prop-1 -ynyl-5-hvdropyrazolo[3,4-d]pyrimidine-4-one, PPPG; 6-amino-3-(3-hydroxyprop- 1-ynyl)1-5-hydropyrazolo[3,4-d]pyrimidine-4-one, HOPPPG; 6-amino-3-(3-aminoprop- 1-ynyl)-5-hydropyrazolo[3,4-d]pyrimidine-4-one, NH 2 PPPG; 4-amino-3-(prop-1-ynyl)pyrazolo[3,4-d]-pyrimidine, PPPA; 4-amino-3-(3-hydroxyprop--ynyl)pyrazolo[3,4-d]pyrimidine, HOPPPA; 4-amino-3-(3-aminoprop-1 -ynyl)pyrazolo[3,4-d]pyrimidine, NH 2 PPPA; 3-prop-1-ynylpyrazolo[3,4-d]pyrimidine-4,6-diamino, (NH 2 ) 2 PPPA; 2-(4,6-disminopyrazolo [3,4-d]pyrimidin-3-yl)ethyn- 1 -ol, (NH 2 ) 2 PPPAOH; 3-(2-aminoethynyl)pyrazolo [3,4-d]pyrimidine-4,6-diamine, (NH 2 ) 2 PPPANH 2 ; 5-prop-1-ynyl-1,3-dihydropyrimidine- 2,4-dione, PU; 5-(3-hydroxyprop-1-ynyl)-1,3-dihydropyrimidine-2,4-dione, HOPU; 6-amino-5-prop-1-ynyl-3-dihydropyrimidine-2-one, PC; 6-amino-5-(3 -hydroxyprop-1-ynyl)-1,3-dihydropyrimidine-2-one, HOPC; and 6-amino-5-(3-aminoprop-1-yny)-1,3-dihydropyrimidine-2-one, NH 2 PC; 5-[4-amino-3-(3-methoxyprop-1-ynyl)pyrazol[3,4-d]pyrimidinyl]-2-(hydroxymethyl)oxolan-3-ol, CH 3 OPPPA; 6-amino-1-[4-hydroxy-5(hydroxymethyl)oxolan-2-yl]-3-(3-methoxyprop- 1-yny- 1)-5-hydropyrazolo [3,4-d]pyrimidin-4-one, CH 3 OPPPG; 5-(4-hydroxybut- 1-ynyl)-1,3-dihydropyrimidine-2,4-dione, HOBuU; 6-amino -5-(4-hydroxybut-1-ynyl)-3-hydropyrimidine-2-one, HOBuC; 4-(4-aminopyrazolo[3,4-d]pyrimidin-3-yl)but-3-yn-1-ol, HOBUPPA; 6-amino-3-(4-hydroxybut-1-ynyl)pyrazolo[3,4-d]pyrimidin-4-ol, HOBuPPG; and 4-(4,6-diaminopyrazolo[3,4-d]pyrimidin-3-yl)but-3-yn-1-ol, (NH 2 ) 2 BuPPAOH; and b) incubating the reaction mixture under reaction conditions that simultaneously allow the AP endonuclease to cleave at a linker site L, thereby generating a free 3′-OH, and the polymerase to extend the primers in a template-specific manner; whereby the target nucleic acid sequence is amplified.