Control of Cell Number in Developing Retina

视网膜发育中细胞数量的控制

• 批准号: 9334004
• 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/9334004
• 关键词: Animals; Area; Atrophic; Binding; Biochemical; Candidate Disease Gene; Cell Count; Cell Death; Cell Differentiation process; Cell Nucleus; Cell Proliferation; Cell membrane; Cells; Complex; DNA Binding; Development; Developmental Biology; Drosophila genus; Experimental Models; Eye; Eye Development; Family; Genes; Genetic Screening; Genetic Transcription; Goals; Grant; Growth; Health; Homologous Gene; Hyperplasia; Integral Membrane Protein; Laboratories; Lead; Mammals; Mediating; Modeling; Molecular; Molecular Genetics; Mutation; Names; Neurofibromin 2; Nuclear; Oncogenes; Organ; Organ Size; Organism; Pathway interactions; Phenotype; Phosphotransferases; Physiological; Process; Protein Kinase; Proteins; 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; cancer stem cell; cell type; combinatorial; compound eye; design; extracellular; human disease; in vivo; insight; mutant; novel; programs; 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。我的实验室使用果蝇的复眼作为实验模型，发现河马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 Ste20 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) 排除在细胞核之外，使其磷酸化和失活，在细胞核中，Yki 通常充当 DNA 结合转录因子 Scalloped (Sd) 的共激活剂。我们的研究进一步确定了河马的关键作用 控制哺乳动物器官大小的途径，强调了果蝇作为发现普遍发育机制的强大模型的重要性。我们最近的大部分努力都集中在发现 Hippo 通路中缺失的成分，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。我们在上一个资助期取得了重大进展，包括1）发现了Crumbs作为一种顶端定位的跨膜蛋白，它通过直接结合和定位肿瘤抑制因子来调节Hippo信号传导至顶膜； 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 途径； 3）发现维替泊芬作为Yki及其哺乳动物同源物YAP的第一个小分子抑制剂； 4) 通过证明 Sd 默认发挥转录抑制因子的作用，发现默认抑制是 Hippo 介导的生长调节的基本机制； 5) 通过证明 Merlin 直接结合和招募效应激酶 Wts 到质膜的需要，阐明 Merlin 调节 Hippo 信号传导的分子机制。在接下来的项目期间，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，我们通过生化筛选鉴定了另一种蛋白激酶，它可以以与 Hpo 类似的方式磷酸化和激活 Wts。我们的目标是表征这种 Hpo 样激酶在生长控制和 河马体内信号传导。其次，我们通过基于表型的筛选，鉴定出了一种以非细胞自主方式调节 Hippo 信号传导的新型肿瘤抑制因子，以及一种以细胞自主方式调节 Hippo 信号传导的肿瘤抑制复合物。我们的目标是了解这些新型肿瘤抑制因子调节 Hippo 通路的分子机制。最后，我们设计了一种敏化基因筛选来识别 Hippo 途径的其他成分。我们的目标是完成遗传筛选并对筛选中确定的候选基因进行分子表征。除了揭示眼睛发育的基本机制外，拟议的研究还将对其他组织的发育产生普遍影响。