This allele was derived by crossing Accn1tm1Lzd mice with mice expressing Cre recombinase under the control of a cytomegalovirus promoter. This resulted in the excision of the exon encoding the second transmembrane domain causing a frameshift and truncating both known splice varients. Truncated mRNA was detectable by in situ hybridization but truncated protein was virtually absent. (J:90117)