Of the eight targeted ES clones that were then injected into C57Bl/6 blastocysts and transferred to foster mothers, one produced chimeric offspring that transmitted the targeted allele through the germline. Their heterozygous offspring were then intermated to produce homozygous nectin-2-null mice (nectin-2LacZ/LacZ). Source
Nectin-2-Null Males Are Infertile
We found nectin-2LacZ/LacZ homozygous mice to be viable and without any gross morphological or behavioral phenotype. Homozygous offspring were present in a mendelian ratio, suggesting that no embryonal lethality is associated with the loss of nectin-2. On further analysis, we determined that homozygous males, but not females, were infertile. Ten nectin-2LacZ/LacZ males (age, 12-20 wk) were each housed with two CD1 females of proven fertility (age, 12 wk) for 3 mo. Although homozygous males showed normal mating behavior and each male produced copulation plugs on numerous occasions, no offspring were ever produced from these matings (data not shown). This confirms the earlier results of Bouchard et al.. We next set out to systematically dissect the male infertility phenotype.