Regulation of Cell and Organ Size in Vivo

描述(申请人提供)：在生物体的发育过程中，大多数组织在发育过程中达到可预测的大小。以时空方式调节单个细胞的生长、增殖和存活以达到最终大小的机制 器官的形状和形状还知之甚少。我们的实验室在果蝇黑腹果蝇身上使用了一种遗传学方法来识别调节细胞增殖和器官大小的基因。在之前的资金周期中，表征的基因包括河马途径的几个组成部分-Aripelago，它编码一种泛素连接酶，针对Cyclin E和Myc进行降解，以及TSC1和TSC2基因。除了在发育过程中调节生长，这些基因很有意义，因为它们的人类同源基因在几种类型的癌症中都发生了突变。我们最近发现，Spitfire基因编码泛素连接酶，对组织生长起负调控作用，并调节细胞表面原钙粘附素脂肪的水平。此外，喷火和脂肪似乎共同定位在顶膜和一群小泡中。我们建议阐明喷火调节脂肪定位和功能的机制。这将通过使用利用质谱学的方法识别喷火的底物以及进行旨在识别喷火的调节者和效应者的基因筛查来实现。我们还将测试喷火是否调节其他信号通路。我们还发现，邻近细胞之间自噬调节因子Atg2表达水平的差异可以影响克隆边界附近的组织生长和细胞生存。我们将确定这种现象是由于自噬在细胞竞争或类似过程中所起的作用，还是ATG基因的一个子集通过自噬非依赖的途径调节细胞的增殖和生存。

DESCRIPTION (provided by applicant): During the development of an organism, most tissues achieve a predictable size during development. The mechanisms that regulate the growth, proliferation and survival of individual cells in a spatiotemporal manner to achieve the final size and shape of the organ are poorly understood. Our laboratory has used a genetic approach in the fruit fly Drosophila melanogaster to identify genes that regulate cell proliferation and organ size. Among the genes characterized in previous funding cycles include several components of the Hippo pathway, archipelago, which encodes a ubiquitin ligase that targets Cyclin E and Myc for degradation and the Tsc1 and Tsc2 genes. In addition to regulating growth during development, these genes are of interest because their human orthologs are mutated in several types of cancer. We have recently found that the spitfire gene, which encodes a ubiquitin ligase, functions as a negative regulator of tissue growth and regulates the levels of the protocadherin Fat at the cell surface. Furthermore Spitfire and Fat appear to co-localize at the apical membrane and in a population of vesicles. We propose to elucidate the mechanism by which Spitfire regulates Fat localization and function. This will be achieved by identifying substrates of Spitfire using approaches that utilize mass spectrometry as well as by conducting genetic screens aimed at identifying regulators and effectors of Spitfire. We will also test whether Spitfire regulates other signaling pathways. We have also found that differences in expression levels of the autophagy regulator Atg2 between neighboring cells can influence tissue growth and cell survival near the clonal boundary. We will determine whether this phenomenon is due to a role for autophagy in cell-competition or similar process or, alternatively, whether a subset of Atg genes has a role in regulating cell proliferation and survival via an autophagy-independent pathway.