Control of Cell Number in Developing Retina

视网膜发育中细胞数量的控制

• 批准号: 9127251
• 负责人: DUOJIA PAN
• 金额: $ 40.5万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-19 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9127251
• 关键词: Alpha Cell; Animals; Apical; Area; Atrophic; Binding; Biochemical; Candidate Disease Gene; Cell Count; Cell Death; Cell Differentiation process; Cell Proliferation; Cell membrane; Cells; Complex; Cyclic AMP-Dependent Protein Kinases; DNA Binding; Development; Developmental Biology; Drosophila eye; Drosophila genus; Experimental Models; Eye; Eye Development; Family; Genes; Genetic Screening; Genetic Transcription; Goals; Grant; Growth; Homologous Gene; Hyperplasia; Integral Membrane Protein; Laboratories; Lead; Malignant Neoplasms; Mammals; Mediating; Modeling; Molecular; Molecular Genetics; Mutation; Names; Neurofibromin 2; Nuclear; Oncoproteins; Organ; Organ Size; Organism; Pathway interactions; Phenotype; Phosphotransferases; Physiological; Process; Protein Kinase; Proteins; Recruitment Activity; Regulation; Repression; Research; Retina; Retinal Diseases; Role; Scallop; Signal Pathway; Signal Transduction; Specific qualifier value; System; Therapeutic Intervention; Tissues; Transcription Repressor/Corepressor; Tumor Suppressor Proteins; Verteporfin; apical membrane; base; cell type; combinatorial; compound eye; design; extracellular; human disease; in vivo; insight; mutant; novel; programs; public health relevance; small molecule inhibitor; stem cell biology; transcription factor

DESCRIPTION (provided by applicant): My long-term scientific goal is to understand the molecular mechanisms that specify retina cell number. Using the compound eye of Drosophila as an experimental model, my laboratory has discovered the Hippo pathway as a central mechanism underlying this process. The core of the Hippo pathway comprises a kinase cascade in which the Ste20 kinase Hippo (Hpo) phosphorylates and activates the NDR family kinase Warts (Wts). Wts, in turn, phosphorylates and inactivates the oncoprotein Yorkie (Yki) by excluding it from the nucleus, where it normally functions as a coactivator for the DNA-binding transcription factor Scalloped (Sd). Our research further established a critical role for the Hippo pathway in controlling organ size in mammals, underscoring the importance of Drosophila as a powerful model to discover universal developmental mechanisms. Much of our recent efforts have focused on discovering the missing components of the Hippo pathway, with the ultimate goal of defining a complete Hippo signaling network that relays information from the extracellular milieu to nuclear gene transcription. We have made significant progress in the last grant period, including 1) the discovery of Crumbs as an apically localized transmembrane protein that regulates Hippo signaling by directly binding and localizing the tumor suppressor Expanded to apical membranes; 2) discovery of a functionally conserved Hippo pathway in organisms representing unicellular relatives of Metazoa; 3) discovery of verteporfin as the first small molecule inhibitor for Yki and its mammalian homologue YAP; 4) discovery of default repression as a fundamental mechanism underlying Hippo-mediated growth regulation by demonstrating that Sd functions by default as a transcriptional repressor; 5) elucidating the molecular mechanism by which Merlin regulates Hippo signaling by demonstrating a requirement for Merlin in direct binding and recruitment of the effector kinase Wts to the plasma membrane. In the coming project period, we will further elucidate the composition and regulation of the Hippo pathway through the following aims. First, we have identified, through biochemical screens, another protein kinase that can phosphorylate and activate Wts in a similar manner as Hpo. Our goal in this aim is to characterize the role of this Hpo-like kinase in growth control and Hippo signaling in vivo. Second, we have identified, through phenotype-based screens, a novel tumor suppressor that regulates Hippo signaling in a non-cell autonomous manner as well as a tumor suppressor complex that regulates Hippo signaling in a cell-autonomous manner. Our goal in this aim is to understand the molecular mechanisms by which these novel tumor suppressors regulate the Hippo pathway. Lastly, we have designed a sensitized genetic screen to identify additional components of the Hippo pathway. Our goal in this aim is to complete the genetic screen and to molecularly characterize candidate genes identified from the screen. Besides revealing fundamental mechanisms of eye development, the proposed studies will have general implications for the development of other tissues.

描述（由申请人提供）：我的长期科学目标是了解指定视网膜细胞数量的分子机制。利用果蝇的复眼作为实验模型，我的实验室发现Hippo通路是这一过程的核心机制。Hippo途径的核心包括激酶级联，其中Ste 20激酶Hippo（Hpo）磷酸化并激活NDR家族激酶Warts（Wts）。反过来，Wts通过将癌蛋白Yorkie（Yki）从细胞核中排除而使其磷酸化和失活，在细胞核中，它通常作为DNA结合转录因子Scalloped（Sd）的共激活因子发挥作用。我们的研究进一步确立了河马的关键作用 在哺乳动物中控制器官大小的途径，强调果蝇作为一个强大的模型，发现普遍的发展机制的重要性。我们最近的大部分努力都集中在发现Hippo通路的缺失组件上，最终目标是定义一个完整的Hippo信号网络，将信息从细胞外环境传递到核基因转录。在上一个资助期，我们取得了重大进展，包括1）发现Crumbs作为一种顶端定位的跨膜蛋白，通过直接结合和定位肿瘤抑制因子Expanded到顶端膜来调节Hippo信号传导; 2）在代表后生动物单细胞亲属的生物体中发现功能保守的Hippo通路; 3）发现维替泊芬作为Yki及其哺乳动物同源物雅普的第一个小分子抑制剂; 4）通过证明Sd作为转录阻遏物默认起作用，发现默认阻遏作为Hippo介导的生长调节的基础机制; 5）通过证明效应激酶Wts直接结合和募集至质膜需要Merlin来阐明Merlin调节Hippo信号传导的分子机制。在未来的项目期间，我们将通过以下目标进一步阐明Hippo通路的组成和调控。首先，我们已经确定，通过生化筛选，另一种蛋白激酶，可以磷酸化和激活WTS以类似的方式作为HPO。我们的目标是描述这种Hpo样激酶在生长控制中的作用， 体内Hippo信号传导。其次，我们已经确定，通过基于表型的筛选，一种新的肿瘤抑制因子，调节Hippo信号在非细胞自主的方式，以及肿瘤抑制因子复合物，调节Hippo信号在细胞自主的方式。我们的目标是了解这些新型肿瘤抑制剂调节Hippo通路的分子机制。最后，我们设计了一个敏感的遗传筛选，以确定其他组成部分的河马途径。我们的目标是完成遗传筛选，并从分子水平上表征筛选出的候选基因。除了揭示眼睛发育的基本机制外，拟议的研究将对其他组织的发育产生普遍影响。