Building and shaping narrow epithelial tubes in C. elegans

项目摘要 我的实验室研究基因和细胞生物学机制，它们形成、塑造和 保护上皮管，重点是非常狭窄的单细胞管和根尖 细胞外基质(AECM)。这两个主题都与人类疾病有关，包括 毛细血管和其他窄管，但在大多数动物模型中研究是具有挑战性的 由于成像相关结构和分子的困难。线虫C. 优雅使我们可以通过对活动物进行成像来绕过这些挑战 在亚细胞分辨率下，结合强大的遗传方法来识别相关的 基因和途径。我们最近的工作表明，单细胞管的形状由以下因素决定：(I) 依赖FusoGen蛋白(AFF-1)的细胞内膜转运事件更好 以其在细胞-细胞融合中的作用而闻名；以及(Ii)一种新发现的AECM类型，它 位于角质层之前，含有的蛋白质与某些 哺乳动物细胞外基质(如富含亮氨酸重复序列、纤溶酶原、透明带、 粘蛋白和/或Nidgen结构域)。这种AECM还依赖于假定的脂类转运蛋白 Lipocalin、清道夫受体B(SCARB)和补丁相关家族。我们的研究 计划将在未来五年跟踪这些进展，以更好地了解 涉及建造单细胞管和结构的具体贩运事件和 AECM的功能。例如，我们将进一步测试AFF-1调解的模型 内吞裂开，允许膜从底部穿梭到根尖表面，以 延伸管腔，我们将确定AFF-1结构域和合作伙伴参与其中 分割函数。我们将研究特定的糖蛋白是如何运输和组装的 在AECM中，转运蛋白家族如何调节适当的AECM脂质含量， 以及单个AECM组件如何影响不同大小的 生物体中的管子。

Project Summary My laboratory studies genes and cell biological mechanisms that form, shape and protect epithelial tubes, with a focus on very narrow unicellular tubes and apical extracellular matrix (aECM). Both are topics relevant to human diseases involving capillaries and other narrow tubes, but are challenging to study in most animal models due to difficulties in imaging the relevant structures and molecules. The nematode C. elegans allows us to circumvent these challenges by permitting imaging of live animals at sub-cellular resolution, combined with powerful genetic approaches to identify relevant genes and pathways. Our recent work showed that a unicellular tube is shaped by: (i) intracellular membrane trafficking events that rely on a fusogen protein (AFF-1) better known for its roles in cell-cell fusion; and (ii) a newly discovered type of aECM that precedes the cuticle and contains proteins similar to those found in or near some mammalian ECMs (e.g. those with leucine-rich repeat, plasminogen, zona pellucida, mucin and/or nidogen domains). This aECM also relies on putative lipid transporters of the lipocalin, scavenger receptor B (SCARB) and Patched-related families. Our research program in the next five years will follow up on these advances to better understand the specific trafficking events involved in building unicellular tubes and the structure and function of the aECM. For example, we will further test the model that AFF-1 mediates endocytic scission to allow membrane to be shuttled from basal to apical surfaces to extend the tube lumen, and we will identify AFF-1 domains and partners involved in this scission function. We will investigate how specific glycoproteins traffic to and assemble within the aECM, how proper aECM lipid content is regulated by transporter families, and how individual aECM components affect the shape and integrity of differently-sized tubes in the organism.