Embryonic stem (ES) cells from a C57BL/6N (B6N) background injected into B6(Cg)-Tyrc-2J/J (B6-albino) recipient blastocysts are commonly used for generating genetically modified mouse models. To understand the influence of the recipient blastocyst strain on germline transmission, BALB/cAnNTac and B6-albino germline transmission rates were compared using the C57BL6/N-derived C2 ES cell line. A total of 92 ES cell clones from 27 constructs were injected. We compared blastocyst yield, birth rate, chimera formation rate, and high-percentage (>50 %) male chimera formation rate. For germline transmission, we analyzed 24 clones from 19 constructs, which generated high-percentage male chimeras from both donor strains. B6-albino hosts resulted in higher mean blastocyst yields per donor than did BALB/c ones (3.6 vs. 2.5). However, BALB/c hosts resulted in a higher birth rate than B6-albino ones (36 vs. 27 %), a higher chimera formation rate (50 vs. 42 %), a higher high-percentage male chimera rate (10 vs. 8 %), and a higher germline transmission rate (65 vs. 49 %), respectively. Our data suggest that BALB/c is a suitable blastocyst host strain for C2 ES cells and has an advantage over the B6-albino strain for receiving the injection of C2 ES cells.
Keywords: Blastocyst microinjection; C57BL/6N ES cells; Chimeric mice; Germline transmission; Pluripotency.