PDF(Pubmed)
Abstract：
Mesenchymal-epithelial transition (MET) is a widely spread and evolutionarily conserved process across species during development. In Ciona embryogenesis, the notochord cells undergo the transition from the non-polarized mesenchymal state into the polarized endothelial-like state to initiate the lumen formation between adjacent cells. Based on previously screened MET-related transcription factors by ATAC-seq and Smart-Seq of notochord cells, Ciona robusta Snail (Ci-Snail) was selected for its high-level expression during this period. Our current knockout results demonstrated that Ci-Snail was required for notochord cell MET. Importantly, overexpression of the transcription factor Brachyury in notochord cells resulted in a similar phenotype with failure of lumen formation and MET. More interestingly, expression of Ci-Snail in the notochord cells at the late tailbud stage could partially rescue the MET defect caused by Brachyury-overexpression. These results indicated an inverse relationship between Ci-Snail and Brachyury during notochord cell MET, which was verified by RT-qPCR analysis. Moreover, the overexpression of Ci-Snail could significantly inhibit the transcription of Brachyury, and the CUT&Tag-qPCR analysis demonstrated that Ci-Snail is directly bound to the upstream region of Brachyury. In summary, we revealed that Ci-Snail promoted the notochord cell MET and was essential for lumen formation via transcriptionally repressing Brachyury.
摘要：
间充质-上皮转化（MET）是在发育过程中跨物种广泛分布且进化保守的过程。在Ciona胚胎发生中，脊索细胞经历从非极化间充质状态到极化内皮样状态的转变，以启动相邻细胞之间的管腔形成。基于先前通过脊索细胞的ATAC-seq和Smart-Seq筛选的MET相关转录因子，选择Cionarobusta蜗牛（Ci-Snail）在此期间的高水平表达。我们目前的敲除结果表明，Ci-Snail是脊索细胞MET所必需的。重要的是,转录因子Brachyury在脊索细胞中的过表达导致类似的表型，管腔形成和MET失败。更有趣的是，尾芽后期Ci-Snail在脊索细胞中的表达可以部分挽救由Brachyury过表达引起的MET缺陷。这些结果表明，在脊索细胞MET期间，Ci-Snail和Brachyury之间存在反比关系，通过RT-qPCR分析验证。此外，Ci-Snail的过表达能显著抑制Brachyury的转录,CUT和Tag-qPCR分析表明，Ci-Snail直接与Brachyury的上游区域结合。总之,我们发现Ci-Snail促进脊索细胞MET，并且通过转录抑制Brachyury对管腔形成至关重要。
