Transcruptional Regulation of Sox9 during endochondral ossification

大多数骨是通过独特的软骨内成骨途径形成的。众所周知，转录因子Sox9对软骨细胞分化至关重要。为了了解软骨形成的分子基础，我们建立了筛选系统，可以让我们识别Sox9的转录辅助因子。我们已经确定p54^<nrb>和Dmrt5是Sox9的一个新的转录伙伴。进一步研究发现p54^<nrb>调控Sox9靶基因的mRNA剪接。此外，我们发现Dmrt5参与了Sox9依赖性的性别分化以及软骨细胞分化。我们的研究结果表明，筛选系统是有效的，新发现的Sox9转录辅助因子对软骨细胞分化很重要。

Most of bones were formed through unique ossification pathway called endochondral ossification. It is well known that transcriptional factor Sox9 is essential for chondrocyte differentiation. To understand the molecular basis for chondrogenesis, we established screening system which can allow us to identify transcriptional co-factor for Sox9. We have identified p54^<nrb> and Dmrt5 as a novel transcriptional partner for Sox9. Further studies revealed that p54^<nrb> modulate mRNA splicing of Sox9 target genes. Moreover, we found that Dmrt5 is involeved in Sox9 dependent sex differentiation as well as chondrocyte differentiation. Our findings indicate that the screening system is valid and the newly identified Sox9 transcriptional cofactor is important for chondrocyte differentiation.