Ras signaling and tubulogenesis in the C. elegans excretory (renal) system

描述(申请人提供)：管子是大多数人体器官的积木。管子发育缺陷会导致严重的出生缺陷，而管子维护缺陷是许多常见健康问题的基础，如肾脏疾病、心脏病和中风。因此，重要的是要了解管子最初是如何形成和维护的。单细胞管是一种特殊的非常微小的管，直径只有一个细胞。哺乳动物在与大脑和肾脏等器官连接的毛细血管床上有许多这样的管。单细胞管似乎也是血管系统中较大内径管的前体。尽管如此，关于单细胞管在体内是如何发育的，以及它们对与更复杂的多细胞管相同的极性通路的依赖程度，人们知之甚少。我们将确定线虫排泄系统中单细胞管发育和维持的分子需求，线虫排泄系统是一个简单的类似肾脏的器官，只由3个单细胞管细胞组成。我们已经确认了 EGF-Ras-ERK途径和许多其他基因对该器官的管状发育或维持具有重要作用。我们将使用这些和其他现有的突变体来洞察两个主要问题。目标1)是什么建立了“尖端向内”的极性，并控制了上皮连接形成的位置，从而形成了单细胞管状结构？我们将(A)使用实时成像技术显示WT和各种突变体中的小管发生，以了解什么细胞接触模式有利于单细胞管的发育；(B)系统地测试单细胞管发育中对已知极性调节因子的要求；(C)进行无偏见的遗传筛选，以发现更多对单细胞管发育重要的基因。目的2)一旦形成，单细胞管连接和管腔是如何维持的，是什么触发了它们的解体？我们将(A)测试两个新发现的顶端定位的跨膜蛋白在顶端区域组织中的作用~(B)测试其中一个蛋白的下调是否与EMT样撤退有关，以及(C)确定管子维持所需的其他基因。我们的实验利用该系统非常简单的解剖学和强大的成像和遗传方法，在线虫中可能解决有关单细胞管的中心问题，这些问题也与所有管的生物学相关。

DESCRIPTION (provided by applicant): Tubes are the building blocks of most human organs. Defects in tube development cause serious birth defects, while defects in tube maintenance underlie many common health problems such as kidney disease, heart disease and stroke. It is therefore important to understand how tubes initially form and are maintained. Unicellular tubes are a special class of very tiny tubes, just one cell in diameter. Mammals have many such tubes in the capillary beds that interface with organs such as the brain and kidney. Unicellular tubes also appear to be precursors to larger bore tubes in the vasculature. Despite this, very little is known about how unicellular tubes develop in vivo or to what degree they rely on the same polarity pathways as more complex multicellular tubes. We will identify molecular requirements for unicellular tube development and maintenance in the C. elegans excretory system, a simple renal-like organ consisting of only 3 unicellular tube cells. We've identified the EGF-Ras-ERK pathway and multiple other genes as important for tube development or maintenance in this organ. We will use these and other existing mutants to gain insight into two main questions. Aim 1) What establishes "apical inward" polarity and controls where epithelial junctions form to create a unicellular tube? We will (a) use live imaging to visualize tubulogenesis in WT and various mutants to ask what patterns of cell contact favor unicellular tube development~ (b) Systematically test the requirements for known polarity regulators in unicellular tube development~ and (c) Conduct unbiased genetic screens to find more genes important for unicellular tube development. Aim 2) Once formed, how are unicellular tube junctions and lumen maintained, and what triggers their disassembly? We will (a) Test the roles of two newly discovered apically-localized transmembrane proteins in apical domain organization~ (b) Test if downregulation of one of these proteins is involved in EMT-like withdrawal~ and (c) Identify additional genes required for tube maintenance. Our experiments take advantage of the system's very simple anatomy and powerful imaging and genetic approaches possible in C. elegans to address central questions about unicellular tubes that are also relevant to the biology of all tubes.