EGF receptor mediated signaling in Drosophila

描述（由申请人提供）：细胞间通讯在许多组织的发育中起重要作用。本研究项目调查了卵子发生过程中激活果蝇表皮生长因子受体（Egfr）的机制，以及介导卵泡细胞中对该受体酪氨酸激酶反应的细胞途径。我们已经证明，果蝇Egfr在卵泡细胞中表达，并从gurken（grk）基因编码的种系接收高度受控的信号。Grk对Egfr的限制性激活启动了几种不同的卵泡细胞反应，并且是卵和胚胎轴形成所需的。我们也发现grk在卵子发生中的表达受到发育输入和减数分裂检查点的调控。我们的目标是研究生殖细胞中Grk产生的分子调控，并分析在卵泡细胞中响应受体激活而激活的图案化和分化过程。我们的具体 目标是：1）grk翻译的调控：我们将鉴定与grk RNA结合的蛋白质，并使用CRISPR技术调控其翻译。我们将确定减数分裂检查点如何调节grk的翻译，并专注于Vasa蛋白与翻译起始因子eIF 1A在检查点激活的种系中的相互作用。我们将对grk RNA进行核糖体足迹分析，这将使我们能够确定发育调节因子和减数分裂检查点对核糖体结合的直接影响。2)分析卵泡细胞对EGFR活化的反应。我们将分析Egfr通路与Notch和JAK/STAT通路在后卵泡细胞分化过程中的协同作用。我们已经分离出了发现Egfr信号与Notch通路相互作用的突变，并将在分子水平上研究这些相互作用。一个焦点是在神经元细胞中作用于Notch下游的转录调节因子哈姆雷特。转录谱分析和ChIP-Seq实验将提供信号通路之间合作的全球分析。我们还将分析后卵泡细胞对Egfr信号的细胞生物学反应，重点是后极化信号的产生及其依赖性 肌动蛋白细胞骨架和微绒毛上。检查点基因的突变以及人类Egfr的不受调节的激活与几种形式的癌症有关。我们的工作将阐明在体内的情况下，控制这种受体的活性的调节机制。它还将分析Egfr和其他信号通路之间的相互作用，并提供在滤泡细胞上皮，上皮发育和分化的模型系统中运作的下游效应通路的分子理解。

DESCRIPTION (provided by applicant): Cell-cell communication plays an important role in the development of many tissues. This research project investigates the mechanisms that activate the Drosophila Epidermal Growth Factor receptor (Egfr) during oogenesis, and the cellular pathways that mediate the response to this receptor tyrosine kinase in the ovarian follicle cells. We have shown that the Drosophila Egfr is expressed in the follicle cells and receives a highly controlled signal from the germline encoded by the gene gurken (grk). Restricted activation of the Egfr by Grk initiates several different follicle cell responses and is required for axis formaton of the egg and embryo. We have also shown that grk expression in oogenesis is regulated by developmental inputs as well as a meiotic checkpoint. Our goal is to study the molecular regulation of Grk production in the germline and to analyze the patterning and differentiation processes that are activated in the follicle cells in response to receptor activation. Our specific aims are: 1) The regulation of grk translation: We will identify proteins that bind to the grk RNA and regulate its translation using CRISPR technology. We will determine how the meiotic checkpoint regulates translation of grk and focus on the interaction of Vasa protein with the translation initiation factor eIF1A in the checkpoint activated germline. We will perform ribosome footprinting assays on the grk RNA which will allow us to determine the direct effects on ribosome binding by the developmental regulatory factors and by the meiotic checkpoint. 2) Analysis of the follicle cell response to EGFR activation. We will analyze the cooperation of the Egfr pathway with the Notch and JAK/STAT pathway during posterior follicle cell differentiation. We have isolated mutations that uncover interactions of Egfr signaling with the Notch pathway and will investigate these interactions at a molecular level. One focus is the transcriptional regulator Hamlet that acts downstream of Notch in neuronal cells. Transcriptional profiling and ChIP-Seq experiments will provide a global analysis of the cooperation between the signaling pathways. We will also analyze the cell biological response to Egfr signaling in the posterior follicle cells with a focus on the production of the posterior polarizing signal and its dependence on the actin cytoskeleton and microvilli. Mutations in checkpoint genes, as well as unregulated activation of the human Egfr have been implicated in several forms of cancer. Our work will elucidate the regulatory mechanisms that control the activity of this receptor in an in vivo situation. It will also analyze the interactions between Egfr and other signaling pathways and provide a molecular understanding of the downstream effector pathways operating in the follicle cell epithelium, a model system for epithelial development and differentiation.