[Transcriptional regulation in chondrogenesis by Sox9].

To identify a group of transcription factors required for chondrogenesis, several researchers tried to detect a chondrocyte-specific enhancer element of Col2a1 gene. Benoit de Crombrugghe's group finally found out 48bp in the first intron of Col2a1 gene as a chondrocyte-specific enhancer element, and moreover they also concluded that binding of homodimer of Sox9 and homo-or heterodimer of Sox5÷Sox6 to this element is indispensable for Col2a1 transcription in chodrocytes. Furthermore, mouse genetic approaches revealed that Sox9, Sox5 and Sox6 are required for chondrogenesis, leading to conclusion that these Sox transcription factors are master regulators in chondrogenesis. Recent studies showed that p300÷CBP, Trap230 (med12) , Wwp2, and Med25 are components of transcriptional machinery of Sox9 in chondrogenesis.