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

描述（由申请人提供）：试管是大多数人体器官的组成部分。输卵管发育缺陷会导致严重的出生缺陷，而输卵管维护缺陷会引发许多常见的健康问题，如肾病、心脏病和中风。因此，了解管道最初是如何形成和维持是很重要的。单细胞管是一类非常微小的特殊管，直径只有一个细胞。哺乳动物的毛细血管床上有许多这样的管子，它们与大脑和肾脏等器官相连。在脉管系统中，单细胞管似乎也是大口径管的前体。尽管如此，对于单细胞管在体内是如何发育的，以及它们在多大程度上依赖于与更复杂的多细胞管相同的极性途径，我们知之甚少。我们将确定秀丽隐杆线虫排泄系统中单细胞管发育和维持的分子需求，这是一个简单的肾样器官，仅由3个单细胞管细胞组成。我们已经确定了

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.