Casc3^{Gt(RRU345)Byg}

A gene trap vector inserted into the intron between exons 3 and 4. The resulting insertional mutation is predicted to constitutively produce a fusion transcript comprised of exons 1-3 of the endogenous gene with the beta-galactosidase (LacZ) gene. Compared to controls, heterozygous mutants showed a 52%-54% whereas homozygous mutants showed a 90%-95% reduction in wild-type mRNA levels. Western analyses of dorsal cortical lysates using CASC3 antibody showed that a single protein product was detected. Compared to controls, wild-type expressed protein level was reduced by 72% in E16.5 homozygous mutant cortices, which was also apparent at E11.5 and E15.5. This suggests that this mutation is a strong hypomorphic allele. (J:240595)