EGF receptor mediated signaling in Drosophila

描述(申请人提供)：细胞间的通讯在许多组织的发育中起着重要的作用。本研究旨在探讨在卵子发生过程中激活果蝇表皮生长因子受体(EGFR)的机制，以及在卵泡细胞中介导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在毛囊细胞中表达，并从由Gurken(Grk)基因编码的生殖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滤泡细胞反应，这是卵子和胚胎轴形成所必需的。我们还表明，在卵子发生中，grk的表达受到发育输入和减数分裂检查点的调节。我们的目标是研究生殖系中Grk产生的分子调控，并分析卵泡细胞中响应受体激活而激活的图案化和分化过程。我们的特定 目的是：1)GRK翻译的调控：我们将识别与GRK RNA结合的蛋白质，并利用CRISPR技术调节其翻译。我们将确定减数分裂检查点如何调节GRK的翻译，并重点研究VASA蛋白与检查点激活的种系中翻译起始因子eIF1A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。其中一个焦点是转录调节因子Hamlet，它在神经细胞中作用于Notch下游。转录图谱和芯片序列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信号的生物学反应，重点是后极化信号的产生及其依赖 在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的无调控激活，都与几种形式的癌症有关。我们的工作将阐明在体内情况下控制该受体活性的调节机制。它还将分析EGFR和其他信号通路之间的相互作用，并提供对毛囊细胞上皮中下游效应通路的分子理解，毛囊细胞上皮是上皮发育和分化的模型系统。

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.