This mutation was generated by cre-mediated deletion of both exon 5 and the neomycin selection cassette from the floxed Vezttm1Smc allele. Presence of the same two major bands on immunoblots of brain and testis protein extracts from wild-type and heterozygous mutant mice indicates absence of a protein product from the mutant allele; these bands are twice as intense for wild-type as for mutant samples.