Identification of Evolutionarily Conserved VSX2 Enhancers in Retinal Development.
Identification of Evolutionarily Conserved VSX2 Enhancers in Retinal Development.
复制标题
视网膜发育中进化保守的 VSX2 增强子的鉴定。
DOI：
10.1101/2023.10.17.562742
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Dyer,MichaelA
中科院分区：
文献类型：
--
作者：
Honnell,Victoria;Sweeney,Shannon;Norrie,Jackie;Ramirez,Cody;Xu,Beisi;Teubner,Brett;Lee,AhYoung;Bell,Claire;Dyer,MichaelA
超级增强子是基因组DNA的扩展区域，它调节与细胞身份和细胞命运有关的基因的表达。最近，我们发现小鼠SE中不同的模块以发育阶段和细胞类型特异性的方式调节主调控转录因子Vsx2的基因表达。Vsx2在视网膜祖细胞以及分化的双极神经元和突触神经胶质中表达。人类和小鼠的VSX2突变由于视网膜祖细胞增殖缺陷导致小眼症。Vsx2 SE中单个模块的缺失会导致小眼症。SE内一个单独模块的缺失会导致双极神经元的完全丧失，但视网膜的其余部分发育正常。此外，Vsx2 SE在脊椎动物中是进化保守的，这表明这些模块对不同物种的视网膜发育很重要。在目前的研究中，我们研究了这些模块驱动物种之间视网膜发育的能力。通过将人构建的Vsx2 SE模块植入小眼症小鼠，恢复了眼睛的大小。为了理解这些SE模块在人类发育模型中的含义，我们生成了人类视网膜类器官。删除一个模块导致小类器官，再现患有小眼症的小鼠的小眼睛表型，而删除另一个模块导致ON锥双极神经元完全丢失。该原型SE可作为具有复杂表达模式的神经源性转录因子解偶联发育阶段和细胞类型特异性效应的模型。此外，通过阐明基因调控机制，我们可以开始研究这些机制的失调如何导致表型多样性和疾病。
Super-enhancers (SEs) are expansive regions of genomic DNA that regulate the expression of genes involved in cell identity and cell fate. Recently, we found that distinct modules within a murine SE regulate gene expression of master regulatory transcription factor Vsx2 in a developmental stage- and cell-type specific manner. Vsx2 is expressed in retinal progenitor cells as well as differentiated bipolar neurons and Müller glia. Mutations in VSX2 in humans and mice lead to microphthalmia due to a defect in retinal progenitor cell proliferation. Deletion of a single module within the Vsx2 SE leads to microphthalmia. Deletion of a separate module within the SE leads to a complete loss of bipolar neurons, yet the remainder of the retina develops normally. Furthermore, the Vsx2 SE is evolutionarily conserved in vertebrates, suggesting that these modules are important for retinal development across species. In the present study, we examine the ability of these modules to drive retinal development between species. By inserting the human build of one Vsx2 SE module into a mouse with microphthalmia, eye size was rescued. To understand the implications of these SE modules in a model of human development, we generated human retinal organoids. Deleting one module results in small organoids, recapitulating the small-eyed phenotype of mice with microphthalmia, while deletion of the other module leads to a complete loss of ON cone bipolar neurons. This prototypical SE serves as a model for uncoupling developmental stage- and cell-type specific effects of neurogenic transcription factors with complex expression patterns. Moreover, by elucidating the gene regulatory mechanisms, we can begin to examine how dysregulation of these mechanisms contributes to phenotypic diversity and disease.