Targeted disruption of the mouse β-adducin gene.

(A) Partial restriction map of a portion of the mouse β-adducin locus with the targeting construct and the resulting targeted allele shown below. Numbered boxes represent exons according to the numbering in humans.7 Asterisks indicate exons containing acceptor splicing sites used in β-adducin alternative splicing. The β-Add63 isoform is generated by unprocessing of the intron located downstream of exon 13.4 The NeoR cassette (NEO) and the thymidine kinase gene (TK) are marked. EcoRI (R) and EcoRV (V) restriction sites are indicated. An 800-bp 3′ flanking fragment (black bar over exon 17) was used as the Southern blot hybridization probe. The expected bands for EcoRI and EcoRV cuts are indicated. (B) DNA of G418 resistant clones was cut with EcoRI (lanes 1-4) or EcoRV (lanes 5-8) and analyzed by Southern blot. Homologous recombination occurred in 2 clones (lanes 1 and 3; and 5 and 7) as indicated by the presence of both wild-type and targeted alleles.