Department of Cell Biology & Human Anatomy, University of California Davis School of Medicine, One Shields Avenue, Davis, CA, 95616, USA.
Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
Sci Rep. 2018 Jul 5;8(1):10195. doi: 10.1038/s41598-018-28420-y.
In vertebrate retinal progenitor cells, the proneural factor Atoh7 exhibits a dynamic tissue and cellular expression pattern. Although the resulting Atoh7 retinal lineage contains all seven major cell types, only retinal ganglion cells require Atoh7 for proper differentiation. Such specificity necessitates complex regulation of Atoh7 transcription during retina development. The Notch signaling pathway is an evolutionarily conserved suppressor of proneural bHLH factor expression. Previous in vivo mouse genetic studies established the cell autonomous suppression of Atoh7 transcription by Notch1, Rbpj and Hes1. Here we identify four CSL binding sites within the Atoh7 proximal regulatory region and demonstrate Rbpj protein interaction at these sequences by in vitro electromobility shift, calorimetry and luciferase assays and, in vivo via colocalization and chromatin immunoprecipitation. We found that Rbpj simultaneously represses Atoh7 transcription using both Notch-dependent and -independent pathways.
在脊椎动物视网膜祖细胞中，神经前体细胞因子 Atoh7 表现出动态的组织和细胞表达模式。尽管由此产生的 Atoh7 视网膜谱系包含所有七种主要细胞类型，但只有视网膜神经节细胞需要 Atoh7 才能正常分化。这种特异性需要在视网膜发育过程中对 Atoh7 转录进行复杂的调节。Notch 信号通路是神经前体细胞碱性螺旋环-螺旋因子表达的一种进化上保守的抑制因子。先前的体内小鼠遗传学研究证实 Notch1、Rbpj 和 Hes1 通过细胞自主抑制 Atoh7 转录。在这里，我们在 Atoh7 近端调控区鉴定了四个 CSL 结合位点，并通过体外电泳迁移率变动、量热法和荧光素酶测定以及体内共定位和染色质免疫沉淀证明了 Rbpj 蛋白在这些序列上的相互作用。我们发现 Rbpj 同时使用 Notch 依赖和非依赖途径来抑制 Atoh7 转录。
