Fig. 4.

TAK1 positively regulates expression of the SOX trio of transcription factors in chondrocytes. (A) SOX9 immunohistochemistry of articular (AC) and growth plate (GP) cartilage sections from 1-month-old Col2a1-CreER^T2; Tak1^f/f (Cre⁺; Tak1^f/f) mice and Cre-negative control littermates (Tak1^f/f) injected with tamoxifen at 1 week of age. (B–D) Primary sternal chondrocytes from Tak1^f/f mice were infected with adenovirus encoding GFP (Ad-GFP), Cre-recombinase (Ad-Cre) or TAK1 (Ad-TAK1). Forty-eight hours later, cells were harvested for western blotting (B) of the indicated proteins or quantitative real-time RT-PCR analyses for the genes involved in signaling (C) or extracellular matrix metabolism (D). *P<0.05, one-way ANOVA followed by Dunnett's test.