Targeted mutation of Adam22 . (A) The genomic structure of the wild-type Adam22 allele (top), the targeting construct (middle) and the disrupted allele (bottom) are shown. ADAM22 expression was disrupted by the insertion of a termination codon and a PGKneo cassette into exon 8. An MC1/TK cassette at the end of the targeting vector allows for negative selection. The 3' probe represents the position of the external probe used for Southern blot analysis, and expected BamHI [B] fragments are indicated by arrows. (B) Southern blot analysis of mouse genomic DNA. The expected DNA fragments for the wild-type allele and disrupted allele are 7.5-kb and 2.5-kb, respectively. +/+, wild-type; +/-, heterozygote; -/-, homozygote. (C) Western blot analysis of ADAM22 expression in the mouse cerebellum. Absence of ADAM22 protein in the Adam22 (-/-) mutant cerebellum was shown using anti-ADAM22-cp (cytoplasmic domain) polyclonal antibody.