Figure 1.
Targeted disruption of the mouse ZnT3 gene. (A) Diagram of the ZnT3 wild-type allele, targeting vector, and predicted mutant allele. The targeting strategy placed nlacZ into the ZnT3 locus, using neor for positive selection and herpes simplex virus thymidine kinase (TK) genes for negative selection. The eight numbered boxes represent exons. Homologous recombination in the regions indicated with an X should result in a mutant allele as shown at the bottom. The black bar represents the 380-bp TaqI/EcoRI probe used for Southern hybridization in B. A, AflII; N, NarI; Nh, NheI; No, NotI; S, StuI. (B) Southern blot of NheI-digested genomic DNA from ZnT3+/+, ZnT3+/−, and ZnT3−/− mice. The probe detects a 7.9-kb mutant and 3.2-kb wild-type fragment. (C) Western blot of brain homogenates from 10-wk-old ZnT3+/+, ZnT3+/−, and ZnT3−/− mice. Equal amounts of total protein were loaded into each well. ZnT3 protein, which migrates as a 39-kD band, was undetectable in the brains of the mutants and reduced in the heterozygotes. The upper, nonspecific band controls for loading differences.