Fig. 1. Targeted disruption of the mouse Dlgh1 gene. (A) The design of the Dlgh1 targeting construct and the structure of the mutant allele. The neo gene is inserted into a ClaI site, and is flanked by 0.85 kb and 8.5 kb homologous sequences at the 5' and 3' sides (thick lines), respectively. The thin lines indicate sequences derived from the pBluescript vector. The locations of the DNA probe used for Southern blot analysis and the PCR primers used for genotyping are indicated. Black boxes represent exons. Bam, BamHI; Cla, ClaI; Eco, EcoRI; Xho, XhoI. (B) Southern blot analysis of tail DNA from F3 progeny using EcoRI-digested genomic DNA. (C) PCR genotyping of Dlgh1^-/- mice. Competitive PCR was performed on genomic tail DNA with three primers (see A): one common 3' primer (R), a 5' Dlgh1-specific primer (F) and a 5' neo-specific primer (N). DNA fragments of 503 bp and 273 bp are amplified from the wild-type and mutant alleles, respectively. (D) Western blot analysis of brain and kidney extracts from Dlgh1^+/+, Dlgh1^+/- and Dlgh1^-/- mice at E15.5. Dlgh1 is not detected in the homozygous mutant mice, and the expression levels of G3PDH are similar among the genotypes.