Letm1^{Gt(CC0204)Wtsi}

The exogenous gene-trap vector sequence, containing an in-frame splice acceptor site followed by coding sequence for a beta-galactosidase/neomycin (beta-Geo) fusion protein, was inserted into the intron following exon 3 (CC0204). The insertion of a trapping vector after exon 3 creates fusion transcripts and premature stop codons, thus preventing the synthesis of full-length mRNA. Full-length mRNA levels are reduced by 50% in heterozygous mutant mice. (J:222017)