Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME 04074, USA.
Biochem Biophys Res Commun. 2013 Jun 7;435(3):356-60. doi: 10.1016/j.bbrc.2013.04.086. Epub 2013 May 7.
Two Snail family genes, Snai1 and Snai2, encode E2 box-binding transcriptional repressors that are important for cartilage development during long bone formation in mice. We demonstrated previously that the Snai1 and Snai2 genes function redundantly, and compensate for each other's loss during mouse chondrogenesis in vivo. A prediction from this genetic data is that the SNAI1 and SNAI2 proteins can bind to each other's promoter to regulate gene expression. Here we demonstrate that expression of Snai1 and Snai2 RNA and protein is induced during chondrogenic differentiation of cultured mouse ATDC5 cells. Using chromatin immunoprecipitation assays, we then show that endogenous SNAI1 and SNAI2 proteins bind to a subset of E2 boxes in both their own and each other's promoter in differentiating ATDC5 cells. Together with our previous genetic data, these results support the model that expression of the Snai1 and Snai2 genes is negatively regulated by their protein products occupying each other's promoter during chondrogenesis, and help provide an explanation for the genetic redundancy observed in the mouse loss of function models.
两个蜗牛家族基因，Snail1 和 Snai2，编码 E2 盒结合转录抑制因子，在小鼠长骨形成过程中对软骨发育很重要。我们之前的研究表明，Snail1 和 Snai2 基因在体内的小鼠软骨发生过程中具有冗余功能，并且可以相互补偿缺失。从该遗传数据预测得出，SNAI1 和 SNAI2 蛋白可以结合到彼此的启动子上以调节基因表达。在这里，我们证明了在培养的小鼠 ATDC5 细胞的软骨分化过程中，Snai1 和 Snai2 RNA 和蛋白的表达被诱导。然后，我们使用染色质免疫沉淀测定法表明，内源性 SNAI1 和 SNAI2 蛋白结合到分化的 ATDC5 细胞中其自身和彼此的启动子的一组 E2 盒。结合我们之前的遗传数据，这些结果支持这样的模型，即 Snai1 和 Snai2 基因的表达受其蛋白产物占据彼此启动子的负调控，有助于解释在小鼠功能丧失模型中观察到的遗传冗余现象。
