Ugcg gene targeting. A, Biosynthetic pathways for GSLs. B, Schema of the Ugcg targeting strategy and cre-mediated recombination of the UgcgloxP allele. UT, untranslated region; Neo, neomycin cassette; TK, thymidine kinase; Probe, location of probe used to select clones. C, Identification of cre-mediated recombination of the UgcgloxP allele in cartilage. Genomic DNA from cartilage and brain was subjected to PCR using primers 1 and 2 to detect the UgcgloxP allele and primers 1 and 3 to detect the UgcgΔ allele. Locations of PCR primers are shown in B. D, Expression of Ugcg mRNA in articular cartilage from wild-type (WT) and Col2-Ugcg−/− mice determined by real time RT-PCR (n = 3 per group). Data shown are mean ± SEM. * = P < 0.05.