Mip^{Gt(OST1231)Lex}

A gene trap vector consisting of LTR sites flanking a beta-geo cassette containing a splice acceptor and a PGK-puro cassette containing a splice donor inserted into exon 1 of the endogenous gene, 168 nucleotides downstream of the start codon. The integration generated a nonsense mutation at codon 57, precluding the translation of ~79% (207 residues) of the protein, including the functionally conserved asparagine-proline-alanine motifs located at codons 68-70 and 184-186. Northern and Western blot analyses indicated an absence of normal transcript and protein in homozygous mutant mice. (J:84775)