B6N.129S6(Cg)-Gt(ROSA)26Sor^{tm2(EGFP/cre)Alj}/J

Gt(ROSA)26Sor^{tm2(EGFP/cre)Alj}

targeted mutation 2

Recombinase-expressing; Reporter

Gt(ROSA)26Sor

gene trap ROSA 26

6

Cre, Cre recombinase, bacteriophage P1; GFP, Green Fluorescent Protein

5432030

FLP excision of the stop signal results in expression of an EGFP-Cre recombinase fusion protein (eGFPcre) in flp-expressing tissues.

129S6/SvEvTac

A targeting vector was constructed to insert an SV40 splice acceptor sequence, an Frt-flanked PGK-neo cassette with polyA sequence, cDNA encoding an EGFP/Cre fusion protein and 3 copies of the SV40 polyA signal into the first intron of Gt(ROSA)26Sor in ES cells. Flp expression will delete the neo cassette, permitting constitutive EGFP/Cre expression in recombined cells and their progeny. In the absence of FLP recombinase, a very small percentage of cells may transiently expresses eGFPCre from the allele during embryonic development or in the adult. Furthermore, males spuriously express eGFPCre in their germline in the absence of FLP recombinase (although the eGFPCre protein is not transmitted to the fertilized egg). No eGFPCre expression is reported in the female germline prior to FLP recombination.

C57BL/6NJ

Mutant mice were bred to C57BL/6NJ inbred mice for many generations to establish this congenic strain. When maintaining a live congenic production colony, homozygous mice may be bred together. The coat color of these mice is expected to be black. On a mixed genetic background (mostly Swiss Webster), R26MASTR males spuriously express eGFPcre in their germline in the absence of FLP recombinase (although the eGFPcre protein is not transmitted to the fertilized egg). No eGFPcre expression is reported in the R26MASTR female germline prior to FLP recombination. Therefore, when designing experiments, it is recommended to breed the R26MASTR allele through the female germline.