Dnajb9^{Gt(KST256)Byg}

The gene trap cassette inserted between adenosine 1151 and guanosine 1152 within intron 1 of the gene, resulting in splicing of exon 1 with the GT cassette and causing premature transcript termination. An increase in beta-galactosidase mRNA and the virtual absence of full length endogenous mRNA confirmed gene disruption in mouse embryonic fibroblasts generated from embryonic day 13.5 homozygous mutant mice. However, variable but detectable expression of full length endogenous mRNA in tissues from adult mutant mice using primers specific for exon 3 confirmed that the insertion of the GT cassette resulted in a hypomorphic allele. (J:226674)