Annealing control primer and its uses

1. A method for improving the annealing specificity of a primer in nucleic acid amplification, comprising:

(a) preparing a 3′-end portion of the primer having a hybridizing nucleotide sequence substantially complementary to a site on a target nucleic acid to hybridize therewith;

(b) forming at the 5′-end of the 3′-end portion a regulator portion comprising at least three contiguous universal bases to have the lowest T m in the three portions of the primer, wherein the regulator portion restricts a primer annealing site to the 3′-end portion to improve the annealing specificity of the 3′-end portion, and

(c) forming at the 5′-end of the regulator portion a 5′-end portion consisting of a pre-selected arbitrary nucleotide sequence substantially not complementary to any site on the target nucleic acid,

whereby the primer has three distinct portions and the annealing specificity of the primer is improved by the presence of the regulator portion and the 5′-end portion, and

wherein the primer has a general formula of 5′-X p -Y q -Z r -3′, wherein X p represents said 5′-end portion consisting of said pre-selected arbitrary nucleotide sequence substantially not complementary to any site on the target nucleic acid; Y q represents said regulator portion comprising at least three contiguous universal bases; Z r represents said 3′-end portion having a hybridizing nucleotide sequence substantially complementary to a site on the target nucleic acid to hybridize therewith; wherein p, q and r represent the number of nucleotides; and wherein X, Y and Z is deoxyribonucleotide or ribonucleotide.

2. The method according to claim 1 , wherein said universal base is selected from the group consisting of deoxyinosine, inosine, 7-deaza-2′-deoxyinosine, 2-aza-2′-deoxyinosine, 2′-OMe inosine, 2′-F inosine, deoxy 3-nitropyrrole, 3-nitropyrrole, 2′-OMe 3-nitropyrrole, 2′-F 3-nitropyrrole, 1-(2′-deoxy-beta-D-ribofuranosyl)-3-nitropyrrole, deoxy 5-nitroindole, 5-nitroindole, 2′-OMe 5-nitroindole, 2′-F 5-nitroindole, deoxy 4-nitrobenzimidazole, 4-nitrobenzimidazole, deoxy 4-aminobenzimidazole, 4-aminobenzimidazole, deoxy nebularine, 2′-F nebularine, 2′-F 4-nitrobenzimidazole, PNA-5-nitroindole, PNA-nebularine, PNA-inosine, PNA-4-nitrobenzimidazole, PNA-3-nitropyrrole, morpholino-5-nitroindole, morpholino-nebularine, morpholino-inosine, morpholino-4-nitrobenzimidazole, morpholino-3-nitropyrrole, phosphoramidate-5-nitroindole, phosphoramidate-nebularine, phosphoramidate-inosine, phosphoramidate-4-nitrobenzimidazole, phosphoramidate-3-nitropyrrole, 2′-0-methoxyethyl inosine, 2′ 0-methoxyethyl nebularine, 2′-0-methoxyethyl 5-nitroindole, 2′-0-methoxyethyl 4-nitro-benzimidazole, 2′-0-methoxyethyl 3-nitropyrrole, and combinations thereof.

3. The method according to claim 1 , wherein said universal base is deoxyinosine, 1-(2′-deoxy-beta-D-ribofuranosyl)-3-nitropyrrole or 5-nitroindole.

4. The method according to claim 1 , wherein p represents an integer of 15 to 60.

5. The method according to claim 1 , wherein q represents an integer of 3 to 15.

6. The method according to claim 1 , wherein r represents an integer of 6 to 30.

7. The method according to claim 1 , wherein p is an integer of 15 to 60, q is an integer of 3 to 15 and r is an integer of 6 to 30.

8. The method according to claim 1 , wherein the method further comprises performing said nucleic acid amplification using a primer pair comprising a forward primer and a reverse primer, at least one of which is the primer having the three portions as set forth in claim 1 .

9. The method according to claim 8 , wherein the method further comprises performing said nucleic acid amplification using a primer pair comprising a forward primer and a reverse primer, both of which are the primer having the three portions as set forth in claim 1 .