The E14.1 ES cell line harbors a spontaneous mutation in this gene. It is not present in the parental 129P2/OlaHsd strain from which the E14.1 ES line is derived. A deletion of 22 nt in exon III results in a frameshift, thereby creating a new in-frame stop codon 63 nt downstream of the original stop codon. Western blot analysis on mutant duodenum lysates confirmed that no detectable protein is expressed from this allele. (J:111779)