Patent ID: 7977055
Filing Date: 2011-07-12
Classification: C12Q

Abstract:
1. A method for amplifying a nucleic acid sequence, which comprises the following steps (I) and (II); (I) a step for preparing a reaction mixture comprising at least the following: a template nucleic acid, deoxyribonucleotide 3-phosphate, a DNA polymerase having a strand displacement activity, endonuclease V, and at least one kind of primer wherein said primer is an oligonucleotide primer which has a nucleotide sequence substantially complementary with the nucleotide sequence of the template nucleic acid and also contains at least one base X which can be recognized by endonuclease V; (II) a step for incubating the reaction mixture prepared in the step (I) for a period of time sufficient for forming an amplification product under sufficient temperature conditions wherein the following reactions are carried out: specific annealing of the primer to the template nucleic acid; elongation chain synthesis reaction and strand displacement reaction by the DNA polymerase; and recognition of a first base X in a nucleic acid chain containing the first base X and a cleavage reaction of a phosphodiester bond positioned at a downstream side (3′ side) of said first base X by the endonuclease V, wherein the first base X is hypoxanthine, wherein the endonuclease V is an endonuclease variant comprising the following mutations, based the amino acid sequence of a wild type endonuclease V of SEQ ID NO:1, (a) the 80th-position amino acid or an amino acid of a position equivalent to the 80th-position of (b) the 105th-position amino acid or an amino acid of a position equivalent the 105th-position of wherein the amino acid Z wherein the amino acid Z