| abstract |
Highly efficient gene integration or gene replacement in the higher eucaryote including animal cells can be performed by using mutant loxP site having the following properties (a)-(c) in the present invention.(a) a nucleotide sequence wherein, in a wild-type loxP site of the following formula (SEQ ID NO: 1) derived from E. coli P1 phage, at least one of the bases consisting of second (T), third (G), fourth (T) and fifth (A) bases, and at least one of the bases consisting of sixth (T) and seventh (G) bases within the 8 bases in the central part of the sequence (spacer region) are substituted by different base, and regions except for the spacer region are optionally substituted by any base:(b) a specific recombination between said mutant loxP and the wild-type loxP site can not occur even in the presence of recombinase Cre; and(c) a specific recombination between the mutant loxP sites having identical nucleotide sequences can occur in the presence of recombinase Cre. |