|Authors||Nichol PF, Botham R, Saijoh Y, Reeder AL, Zaremba KM|
|Journal||J. Pediatr. Surg. Volume: 46 Issue: 9 Pages: 1711-9|
|Publish Date||2011 Sep|
The generation of nonviable homozygous null mouse embryos from heterozygote null/+ breedings can be highly resource consuming, with only 25% of the embryos in the litter being null mutants. We hypothesized that (1) we could double the number of homozygous null mouse embryos in a litter without reducing litter size using Hypoxanthine-guanine phosphoribosyltransferase-Cre (Hprt)-Cre (which is active in the female germ line at the time of fertilization), and (2) these homozygous null mutants would be identical to mutants generated through traditional null/+ breedings.To test this hypothesis, we used a conditional allele Fgfr2IIIb(flox). This allele when recombined is identical to the Fgfr2IIIb(null) allele. An F1 generation of Fgfr2IIIb(rec/) females was created by mating Fgfr2IIIb(); Hprt(cre)(/cre) females to a Fgfr2IIIb(flox/flox) male. The F1 females were then mated to a Fgfr2IIIb(flox/flox) male. F2 embryos were genotyped, and the morphology and histology of the lungs, intestine, limbs, and brain were analyzed.The Hprt-Cre mating strategy results in 51% of pups being genotypic homozygous null embryos (85/166) vs 23% for the standard null/+ approach (38/167). These embryos did not express the Fgfr2IIIb transcript and were phenotypically identical to null embryos generated through standard null/+ breedings.The Hprt-Cre mating strategy increases the number of homozygous mutant embryos in a litter without decreasing litter size. Embryos generated through this approach are phenotypically identical to those from standard heterozygous breedings. We recommend this approach to investigators using a model system that relies on the generation of homozygous null embryos.
|Full Text||Full text available on PubMed Central|