Oca2^p-un

This mutation comprises a head-to-tail tandem duplication of ~70 kb and includes an intracisternal A particle (IAP) that is present in the wild-type allele. The ~1.3-kb larger mutant transcript contains a tandem repetition of nucleotides 765-2067, derived from exons 6-18, with apparent breakpoints in introns 5 and 18; the duplicated region encodes amino acids 212-645, encompassing transmembrane domains 2-7, with serine substituted for alanine at the junction of the second copy. Several phenotypic revertant alleles have been shown to have lost one copy of the duplicated segment. (J:3762, J:11138, J:32816)