Retinal differentiation in Drosophila.
Retinal differentiation in Drosophila.
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DOI：
10.1002/wdev.100
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发表时间：
2013-07
期刊：
影响因子：
--
通讯作者：
Treisman JE
中科院分区：
文献类型：
--
作者：
Treisman JE
果蝇眼睛的发育已经被广泛研究，因为基因筛选突变破坏了这一过程。在胚胎和幼虫发育过程中，眼睛的成虫盘由Pax6同源物Eyeless和下游转录因子网络指定。这些因子的表达受信号分子调节，也间接受眼盘生长的调节。光感受器簇的分化在第三龄幼虫眼盘后部开始，并由分泌的蛋白Hedgehog驱动向前发展。在每个簇内，刺猬信号和Notch介导的侧抑制的组合活动诱导和细化转录因子Atonal的表达，其指定每个小眼的创始R8光感受器。七个额外的光感受器，其次是锥细胞和色素细胞，相继被信号分子斯皮茨，德尔塔和七无新娘招募。这些信号和内在转录因子的组合赋予每个小眼细胞其特定的身份。在蛹阶段，视紫红质表达，光感受器和辅助细胞呈现其最终位置和形态以形成成体视网膜。在过去的几十年里，对这种以重复结构排列的少量细胞类型的遗传分析已经允许对控制细胞分化和形态学重排的基本机制有了非常详细的了解。
Drosophila eye development has been extensively studied, due to the ease of genetic screens for mutations disrupting this process. The eye imaginal disc is specified during embryonic and larval development by the Pax6 homolog Eyeless and a network of downstream transcription factors. Expression of these factors is regulated by signaling molecules and also indirectly by growth of the eye disc. Differentiation of photoreceptor clusters initiates in the third larval instar at the posterior of the eye disc and progresses anteriorly, driven by the secreted protein Hedgehog. Within each cluster, the combined activities of Hedgehog signaling and Notch-mediated lateral inhibition induce and refine the expression of the transcription factor Atonal, which specifies the founding R8 photoreceptor of each ommatidium. Seven additional photoreceptors, followed by cone and pigment cells, are successively recruited by the signaling molecules Spitz, Delta, and Bride of sevenless. Combinations of these signals and of intrinsic transcription factors give each ommatidial cell its specific identity. During the pupal stages, Rhodopsins are expressed, and the photoreceptors and accessory cells take on their final positions and morphologies to form the adult retina. Over the past few decades, the genetic analysis of this small number of cell types arranged in a repetitive structure has allowed a remarkably detailed understanding of the basic mechanisms controlling cell differentiation and morphological rearrangement.