Ras Signaling and Tubulogenesis in the C. elegans Excretory (renal) System

 描述（由申请人提供）：器官由具有不同大小、形状和功能的专门管类型的网络组成，最小的（“单细胞”）管直径仅为一个细胞。输卵管发育或维护缺陷是许多严重健康问题的基础，如肾脏疾病，心脏病和中风，因此了解塑造和维护输卵管的因素非常重要。尽管单细胞管广泛存在于与其他组织（如脑和肾）接触的毛细血管床中，但对单细胞管如何发育或维持知之甚少。为了解决这些问题，我们研究了一组单细胞管排泄（肾样）系统的线虫C。优雅.我们确定了超过100种影响这些单细胞管的突变体，我们将用它们来解决三个主要问题。目的1）Ras信号传导和融合剂AFF-1如何促进细长管形状？许多单细胞管是无缝的--它们沿其长度沿着缺乏连接--它们采用细长或分支的形状。我们将测试的假设，aff-1是一个关键的下游目标的Ras信号传导的无缝和管形状控制，并具有连续的功能，在一个新的途径顶端膜添加。目的2）管腔细胞外基质如何保护输卵管的完整性？随着管的发育，它们将各种糖蛋白分泌到它们的管腔中。我们将测试的假设，即透明带（ZP）域蛋白LET-653与其他基因产物，我们确定形成一个管腔基质支架，形状和保护管腔管形态发生过程中，和单细胞管是特别依赖于这样的管腔支架的完整性。目的3）Ras信号传导如何促进管分层？上皮内的一些细胞可以分层并产生其他细胞类型，并且该过程在肿瘤细胞转移期间被增选。我们确定了一个细胞的非自治要求Ras信号分层。我们将测试的假设，Ras的行为在一个共同的途径与其他基因，我们已经确定，也需要分层。我们的实验利用了C.优雅地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有关。

 DESCRIPTION (provided by applicant): Organs are made up of networks of specialized tube types that have distinct sizes, shapes and functions, with the tiniest ("unicellular") tubes being just one cell in diameter. Defects in tube development or maintenance underlie many serious health problems such as kidney disease, heart disease and stroke, so it is important to understand factors that shape and maintain tubes. Despite the fact that unicellular tubes are widespread in the capillary beds that interface with other tissues such as the brain and kidney, very little is known about how unicellular tubes develop or are maintained. To address these issues, we study a set of unicellular tubes in the excretory (renal-like) system of the nematode C. elegant. We identified >100 mutants that affect these unicellular tubes, and we will use them to address three main questions. Aim 1) How do Ras signaling and the fusogen AFF-1 promote an elongated tube shape? Many unicellular tubes are seamless -they lack junctions along their length - and they adopt elongated or branched shapes. We will test the hypothesis that aff-1 is a key downstream target of Ras signaling for both seamlessness and tube shape control and has a continuous function in a novel pathway for apical membrane addition. Aim 2) How does the luminal extracellular matrix protect tube integrity? As tubes develop, they secrete various glycoproteins into their lumens. We will test the hypothesis that the Zona Pellucida (ZP) domain protein LET-653 interacts with other gene products we identified to form a luminal matrix scaffold that shapes and protects the lumen during tube morphogenesis, and that unicellular tubes are particularly reliant on such luminal scaffolds for their integrity. Aim 3) How does Ras signaling promote tube delamination? Some cells within an epithelium can delaminate and give rise to other cell types, and this process is co-opted during tumor cell metastasis. We identified a cell non-autonomous requirement for Ras signaling in delamination. We will test the hypothesis that Ras acts in a common pathway with other genes we've identified that are also required for delamination. Our experiments take advantage of powerful imaging and genetic approaches possible in C. elegant to address central questions about unicellular tubes that are also relevant to the biology of all tubes.