Hazelett D J, Bourouis M, Walldorf U, Treisman J E
Skirball Institute for Biomolecular Medicine and Department of Cell Biology, NYU Medical Center, New York, NY 10016, USA.
Development. 1998 Sep;125(18):3741-51. doi: 10.1242/dev.125.18.3741.
Signaling by the secreted hedgehog, decapentaplegic and wingless proteins organizes the pattern of photoreceptor differentiation within the Drosophila eye imaginal disc; hedgehog and decapentaplegic are required for differentiation to initiate at the posterior margin and progress across the disc, while wingless prevents it from initiating at the lateral margins. Our analysis of these interactions has shown that initiation requires both the presence of decapentaplegic and the absence of wingless, which inhibits photoreceptor differentiation downstream of the reception of the decapentaplegic signal. However, wingless is unable to inhibit differentiation driven by activation of the epidermal growth factor receptor pathway. The effect of wingless is subject to regional variations in control, as the anterior margin of the disc is insensitive to wingless inhibition. The eyes absent and eyegone genes encode members of a group of nuclear proteins required to specify the fate of the eye imaginal disc. We show that both eyes absent and eyegone are required for normal activation of decapentaplegic expression at the posterior and lateral margins of the disc, and repression of wingless expression in presumptive retinal tissue. The requirement for eyegone can be alleviated by inhibition of the wingless signaling pathway, suggesting that eyegone promotes eye development primarily by repressing wingless. These results provide a link between the early specification and later differentiation of the eye disc.
分泌型刺猬蛋白（hedgehog）、果蝇转化生长因子-β（decapentaplegic）和无翅蛋白（wingless）发出的信号，在果蝇眼成虫盘内组织光感受器分化模式；刺猬蛋白和果蝇转化生长因子-β是分化从后缘开始并在整个成虫盘推进所必需的，而无翅蛋白则阻止其在侧缘开始。我们对这些相互作用的分析表明，起始需要果蝇转化生长因子-β的存在以及无翅蛋白的缺失，无翅蛋白在果蝇转化生长因子-β信号接收下游抑制光感受器分化。然而，无翅蛋白无法抑制由表皮生长因子受体途径激活所驱动的分化。无翅蛋白的作用受到控制上的区域差异影响，因为成虫盘的前缘对无翅蛋白的抑制不敏感。无眼（eyes absent）和眼缺失（eyegone）基因编码一组确定眼成虫盘命运所需的核蛋白成员。我们表明，无眼和眼缺失对于成虫盘后缘和侧缘果蝇转化生长因子-β表达的正常激活以及假定视网膜组织中无翅蛋白表达的抑制都是必需的。通过抑制无翅蛋白信号通路可以减轻对眼缺失的需求，这表明眼缺失主要通过抑制无翅蛋白来促进眼睛发育。这些结果在眼盘的早期特化和后期分化之间建立了联系。
