Tube size control by Src and Yorkie/YAP

描述(由申请人提供)：人体器官的功能，如肺、肾和血管系统，关键依赖于形成正确直径和长度的管子的细胞。然而，人们对管子大小的控制机制知之甚少。这反映在许多人类疾病缺乏有效的治疗方法，其中管子大小控制有缺陷，如多囊肾病，以及我们无法控制管子大小来治疗非直接由管子大小缺陷引起的疾病。例如，阻止血管大小生长的药物可以用作抗血管生成药物来阻止实体肿瘤的生长。这项拟议的研究将以果蝇气管为模型系统，对控制管子大小的多种机制的三个方面进行定义。果蝇气管是上皮管的分支网络，起着肺/血管系统的联合作用，为利用体内方法和技术研究管子大小控制的基本机制提供了强大的分子/遗传系统，这在脊椎动物模型中是困难或不可行的。我们的数据表明，在果蝇气管和小鼠胚胎主动脉的发育过程中，保守的Src激酶家族成员控制着细胞的生长方向，而果蝇Forin dDAAM与Src42共同作用于气管细胞的生长方向。值得注意的是，Src42和dDAAM形成了一个复合体，它定义了一条不同于已知的顶端/基底极性和平面细胞极性途径的新的极性途径。为第一个目的提出的实验将确定src42和dDAAM是否起到发送或接收定向生长信号的作用，dDAAM是作为src的调节器还是效应器，并确定src42和dDAAM定向功能的效应器。在第二个目标中，我们将验证细胞体积增加调节气管细胞顶膜范围的假说，并确定哪些基因和途径介导了src42和dDAAM控制气管顶端表面积的能力。对于第三个目的，我们的初步数据表明，转录因子York kie在保守的细胞生长和增殖途径中发挥作用，尽管气管系统中没有细胞凋亡，但它通过一种名为果蝇凋亡抑制因子(DiAP)的细胞死亡(凋亡)基因来控制管道的大小。在这个目标中，我们将检验约克人的假设 也是控制气管大小的五个已知通路中的一个或多个的效应器 作为检验，假设DIAP通过典型的凋亡因子蛋白的子集来调节管子的大小。总之，拟议中的实验结果将为调控管子大小控制的分子机制提供关键的见解，这最终应该会导致治疗上操纵管子大小的能力。

DESCRIPTION (provided by applicant): The function of human organs such as the lung, kidney and vascular system are critically dependent on cells forming tubes of the correct diameter and length. However, the mechanisms controlling tube size are poorly understood. This is reflected in a lack of effective treatments for many human diseases in which tube-size control is defective, such as polycystic kidney disease, and our inability to control tube size to treat diseases that are not directly due to tube-size defects. For example, drugs that block vascular tube-size growth could be used as anti-angiogenic drugs to block solid tumor growth. The proposed research would define three aspects of the multiple mechanisms that control tube- size using the Drosophila tracheal as a model system. Drosophila trachea are a ramifying network of epithelial tubes that function as a combined pulmonary/vascular system and provides a powerful molecular/genetic system for investigating the basic mechanisms of tube-size control using in vivo approaches and techniques that are difficult or infeasible with vertebrate models. Our data show that members of the conserved Src kinase family control the orientation of cell growth during development of the Drosophila trachea and the embryonic mouse aorta, and that the Drosophila formin dDAAM works with Src42 to orient tracheal cell growth. Strikingly, Src42 and dDAAM form a complex that defines a new polarity pathway that is distinct from known apical/basal polarity and planar cell polarity pathways. The experiments proposed for the first aim would determine whether Src42 and dDAAM act to send or to receive signals that orient growth, whether dDAAM acts as a regulator or an effector of Src, and identify effectors of the Src42 and dDAAM orientation function. In the second aim, we will test the hypothesis that increases in cell volume regulate the extent of tracheal cell apical membrane and identify which genes and pathways mediate the ability of Src42 and dDAAM to control the tracheal apical surface area. For the third aim, our preliminary data show that the transcription factor Yorkie, which acts in conserved cell growth and proliferation pathways, controls tube size through the cell death (apoptosis) gene named Drosophila inhibitor of apoptosis (DIAP), despite the fact that there is no apoptosis in the tracheal system. In this aim, we will test that hypothesis that Yorkie is the effector of one or more of the five known pathways that controls tracheal tube size, as well as test the hypothesis that DIAP acts through a subset of canonical apoptosisfector proteins to regulate tube size. Together, the results of the proposed experiments will provide critical insights into the molecular mechanisms that regulate tube-size control, which should ultimately lead to the ability to therapeutically manipulate tube size.