Fig. 1. Generation of 10 integrin-null mice. (A) Organization of the mouse 10 integrin gene, targeting construct and recombinant allele. Exons are numbered and indicated by black boxes. EGFP, enhanced green fluorescent protein; NEO, neomycin resistance gene. Relevant restriction sites: X, XbaI; N, NotI. Probe denotes the external probe used for Southern genotyping. which detects (B) Southern blot analysis of mouse tail DNA derived from progeny of heterozygous breeding (+/+, wild-type; +/–, heterozygous; –/– homozygous mutant). The 10 integrin probe indicated in A detects a 10 kb fragment and a 5.5 kb fragment in the wild type and knockout alleles, respectively. (C) RT-PCR analysis of mRNA isolated from the heart indicates a complete lack of the 10 integrin transcript in homozygous mutant (–/–) mice. st, molecular weight standards. (D) Immunohistochemical staining of the knee region from newborn wild-type and mutant mice using an 10 integrin-specific polyclonal antibody. Mutant chondrocytes show negative staining for 10 integrin. Bar, 100 µm.