Figure 1.

Generation of USAG1^–/– mutation by gene targeting. (A) USAG1–null allele was generated by homologous recombination in ES cells. Exon 1 (black box) and part of the intron were replaced with a lacZ gene (white box) and the NeoR cassette (gray box). (B) Analysis of USAG1^+/+ (WT) and correctly targeted heterozygous (Hetero) ES cell clones by Southern blot analysis using 5′ genomic probe (thick black line in A). (C) PCR genotyping of F₂ littermates. Template(–) is the negative control. (D) Northern blot analysis of USAG1 mRNA in the kidney of USAG1^+/+ and USAG1^–/– (KO) mice.