Fig. 7.

CaMKIV stimulates collagen type X (Col X) promoter activity and induces expression of chondrocyte differentiation markers. A: chondrocytes were transiently transfected with Col X promoter and expression vectors encoding active CaMKIV or inactive CaMKIV as indicated in the presence or absence of HDAC4. CaMKIV overcomes HDAC4 repression of Col X promoter activity. B: HDAC4 was transfected into chondrocytes with active CaMKIV or inactive CaMKIV. Forty-eight hours later, RNA was isolated and qRT-PCR was used to quantitate expression of Col X, Ihh, and Sox 9. Values represent means ± SD from 3 independent experiments. *P < 0.05.