The genetic dissection of seamless tube shape control in the Drosophila trachea

果蝇气管无缝管形状控制的遗传解析

• 批准号: 9123783
• 负责人: Jeffrey B Rosa
• 金额: $ 4.36万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2019-09-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9123783
• 关键词: Actins; Actomyosin; Address; Adopted; Affect; Apical; Architecture; Binding; Biogenesis; Biological; Blood Vessels; Cells; Chitin; Chitin Synthase; Complex; Contracts; Cyst; Defect; Disease; Dissection; Drosophila genus; Drosophila melanogaster; Endothelial Cells; Epithelial; Epithelial Cells; Epithelium; Exhibits; Extracellular Matrix; Fiber; Fibrinogen; Filament; Gases; Genes; Genetic; Glycocalyx; Glycoproteins; Growth; Health; Homeostasis; Imaging Techniques; Immunofluorescence Immunologic; In Situ; Individual; Insecta; Larva; Lasers; Lead; Measures; Mediating; Membrane; Modeling; Molecular; Morphogenesis; Morphology; Myosin ATPase; Myosin Type II; Nature; Nutrient; Organ; Pathway interactions; Phenocopy; Polycystic Kidney Diseases; Polysaccharides; Positioning Attribute; Property; Proteins; Proteoglycan; Regulation; Resolution; Role; Shapes; Stereotyping; Structure; Surface; System; Testing; Tissues; Trachea; Transmission Electron Microscopy; Tube; Tubular formation; Vascular System; Zinc Fingers; apical membrane; asthmatic; base; cerebral cavernous malformations; dosage; genetic approach; innovation; live cell imaging; loss of function; mutant; neovascularization; non-muscle myosin; novel; overexpression; polarized cell; programs; public health relevance; research study; respiratory; transcription factor; tumor

 DESCRIPTION (provided by applicant): To build a functional vascular network, endothelial tubes must adopt stereotyped topologies. Both multicellular and unicellular tube topologies are observed in vertebrate vasculatures. Seamless tubes are unicellular and unbound by junctions. Seamless tubes are found in multiple contexts within vertebrate vascular networks. The functional roles of seamless tubes in these contexts are poorly understood because the cellular mechanisms of seamless tube morphogenesis are poorly understood. Nevertheless, seamless tubes are conserved across phyla, including in the respiratory (tracheal) system of Drosophila melanogaster larvae, where powerful forward genetic approaches can be utilized to study seamless tube morphogenesis. To build a functional vascular network, endothelial tubes must also adopt a stereotyped shape. Endothelial cells secrete a luminal (apical) extracellular matrix (aECM) called the glycocalyx, comprised of secreted and membrane-bound glycoproteins and proteoglycans. Defects in glycocalyx structure lead to defects in endothelial tube expansion. Indeed, aECMs have a conserved role in regulating tube growth, including in Drosophila tracheal tubes. The seamless tubes of the Drosophila trachea secrete a chitin-based aECM called the cuticle, whose role in seamless tube morphogenesis not known. We have a poor understanding of molecular pathways through which individual secreted matrix factors are organized into an ordered aECM. Moreover, the molecular pathways through which aECMs shape the apical membrane to regulate tube morphogenesis are entirely unknown. I will use the seamless tubes of the Drosophila larval tracheal system as a model to elucidate novel genetic pathways controlling seamless tube shape by regulating aECM structure/function. I have identified a role for the seamless tube aECM in regulating tube shape and integrity. Chitin synthase-deficient terminal cells exhibit apical membrane cysts and discontinuities. I have also identified a set of novel mutants (ichor and asthmatic) that phenocopy "chitin biogenesis" mutants. I hypothesize that these mutants may affect novel pathway(s) regulating the structure or function of a seamless tube aECM. ichor and asthmatic encode zinc- finger transcription factors (CG11966 and zif, respectively), suggesting they regulate the expression or targeting of aECM components to the lumen. In Specific Aim 1, I will identify the genetic requirements for aECM organization in seamless tubes, including testing the role of a conserved polarity factor known to be downstream of Zif, in targeting aECM components to the lumen. In Specific Aim 2, I will identify cellular and molecular pathways through which the seamless tube aECM regulates tube shape. I will test a role for the seamless tube aECM in regulating apical actomyosin organization using both genetic and innovative live cell imaging techniques.

 描述（由申请人提供）：为了构建功能性血管网络，内皮管必须采用定型拓扑。在脊椎动物脉管系统中观察到多细胞和单细胞管拓扑结构。无缝管是单细胞的并且不受连接处束缚。无缝管存在于脊椎动物血管网络的多种环境中。由于对无缝管形态发生的细胞机制知之甚少，因此人们对无缝管在这些情况下的功能作用知之甚少。尽管如此，无缝管在整个门中都是保守的，包括在果蝇幼虫的呼吸（气管）系统中，可以利用强大的正向遗传方法来研究无缝管形态发生。为了构建功能性血管网络，内皮管也必须采用定型形状。内皮细胞分泌一种称为糖萼的管腔（顶端）细胞外基质 (aECM)，由分泌的膜结合糖蛋白和蛋白聚糖组成。糖萼结构的缺陷导致内皮管扩张缺陷。事实上，aECM 在调节管生长方面具有保守的作用，包括在果蝇气管中。果蝇气管的无缝管分泌一种基于几丁质的 aECM，称为角质层，其在无缝管形态发生中的作用尚不清楚。我们对个体分泌基质因子被组织成有序 aECM 的分子途径知之甚少。此外，aECM 塑造顶膜以调节管形态发生的分子途径完全未知。我将使用果蝇幼虫气管系统的无缝管作为模型，阐明通过调节 aECM 结构/功能来控制无缝管形状的新遗传途径。我已经确定了无缝管 aECM 在调节管形状和完整性方面的作用。几丁质合酶缺陷的终末细胞表现出顶膜囊肿和不连续性。我还鉴定了一组新的突变体（脓液和哮喘），它们表现出“几丁质生物发生”突变体的表型。我假设这些突变体可能会影响调节无缝管 aECM 结构或功能的新途径。脓液和哮喘编码锌指转录因子（分别为 CG11966 和 zif），表明它们调节 aECM 成分的表达或靶向管腔。在具体目标 1 中，我将确定无缝管中 aECM 组织的遗传要求，包括测试 Zif 下游已知的保守极性因子在将 aECM 成分靶向管腔时的作用。在具体目标 2 中，我将确定无缝管 aECM 调节管形状的细胞和分子途径。我将使用遗传和创新的活细胞成像技术来测试无缝管 aECM 在调节顶端肌动球蛋白组织中的作用。