Inactivation of SOXC genes in the Prg4+ cell lineage does not affect joint integrity in young mice. A, Schematic of experimental timeline. Tmx, tamoxifen injections. P0 to P60, postnatal days 0 to 60. B, In situ hybridization of adjacent knee sections with Sox4, and Sox11 RNA probes in mice at P60. C, Fold changes in relative levels of Sox4 and Sox11 RNAs in pools of knee and hip synovium tissue, as assessed by RT-qPCR. 3 mice were used for each genotype. *, p<0.05; **, p<0.01. D and E, Safranin-O staining (cartilage matrix) and fast green counterstaining of knee synovium and tibial plateau articular cartilage, respectively.