Role of Wnt/Frizzled signaling during eye development

描述（由申请人提供）：在脊椎动物眼睛的发育过程中，会发生复杂的模式事件，导致不同组织成分的产生。多种先天性眼部疾病，包括无眼症或小眼症、无虹膜、结肠瘤和视网膜发育不良，都源于早期眼睛发育的中断。因此，确定导致眼部组织，特别是视网膜和视网膜色素上皮（RPE）的模式和分化的机制至关重要。介导模式事件的分子信号在很大程度上是未知的。wnt配体家族的成员是多种组织中细胞增殖、细胞命运决定和组织极性的重要调节因子。wnt通过结合跨膜受体的卷曲家族成员而起作用。然而，尽管多个Wnt和Frizzled在眼睛发育的不同阶段表达，但尚未研究过Wnt/Frizzled信号在脊椎动物眼睛发育中的作用。我们提供的证据表明，Wnt/ β -连环蛋白信号在视泡中是活跃的，并假设它调节视网膜祖细胞增殖和RPE的发展。为了验证这一点，我们提出在小鼠、小鸡和爪蟾身上进行实验，因为每种模型系统都具有独特的实验优势。我们将在转基因爪蟾和小鼠胚胎中使用Wnt/ β - catenin信号报告基因来确定该信号通路在眼睛发育过程中的活跃时间和位置（目的1）。然后，我们将测试Wnt/ β -连环蛋白信号是否通过干扰小鸡和爪蟾眼睛发育不同阶段的信号通路来调节祖细胞增殖和RPE发育（目的2）。最后，我们将确定这些作用是否由frizzled5受体介导，该受体在发育中的视神经泡中选择性表达（目的3）。总之，这些实验将促进我们对发育过程中形成眼睛模式的信号的理解，并可能为这些模式事件如何在先天性眼病中被破坏提供线索。此外，这些研究应该对Wnt/ β -连环蛋白信号在神经系统发育过程中的作用提供更全面的了解。

DESCRIPTION (provided by applicant): During development of the vertebrate eye, complex patterning events occur which result in the generation of distinct tissue components. Multiple congenital eye disorders, including anophthalmia or micropthalmia, aniridia, coloboma and retinal dysplasia, stem from disruptions in early eye development. Thus, it is critical to define the mechanisms that lead to the patterning and differentiation of ocular tissues, in particular the retina and retinal pigment epithelium (RPE). The molecular signals that mediate patterning events are, for the most part, unknown. Members of the wnt family of ligands are important regulators of cellular proliferation, cell fate decisions and tissue polarity in multiple tissues. Wnts act by binding to members of the Frizzled family of transmembrane receptors. However, the role of Wnt/Frizzled signaling in vertebrate eye development has not been examined, despite the fact that multiple Wnts and Frizzleds are expressed at various stages of eye development. We provide evidence that Wnt/beta-catenin signaling is active in the optic vesicle and hypothesize that it regulates retinal progenitor proliferation and RPE development. To test this we propose experiments in mouse, chick and Xenopus, since each model system offers unique experimental advantages. We will use a reporter of Wnt/beta catenin signaling in transgenic Xenopus and mouse embryos to define when and where during eye development this signaling pathway is active (Aim 1). We will then test whether Wnt/beta-catenin signaling regulates progenitor proliferation and RPE development by perturbing this signaling pathway at various stages of eye development in both chick and Xenopus (Aims 2). Finally, we will determine whether these effects are mediated by the Frizzled-5 receptor, which is selectively expressed in the developing optic vesicle (Aim 3). Together, these experiments will advance our understanding of the signals that pattern the eye during development and may provide clues about how these patterning events are disrupted in congenital eye disorders. In addition, these studies should provide more general insight into the role of Wnt/beta-catenin signaling during nervous system development.