New genes affecting the SREBP pathway in mammalian and drosophila cells

描述：（申请人提供） 在过去的四年里，我们用突变的哺乳动物细胞克隆 三个新基因对调节胆固醇的SREBP途径至关重要 以及哺乳动物细胞中的脂肪酸代谢。这些 SREBP裂解激活蛋白（SCAP）、Site-1蛋白酶 (S1P)和位点2蛋白酶（S2 P）。突变细胞也被证明是至关重要的 我们对这些基因座功能的分析。我们将继续使用 哺乳动物细胞遗传学的工具，以追求的假设， 调节SREBP信号通路的必需基因仍有待进一步研究。 发现了特别是，我们试图确定编码一个假定的 “ER滞留蛋白”是固醇调节的运动所必需的， SCAP/SREBP复合物位于内质网（ER）和高尔基体之间。 这种蛋白质可能是胆固醇反馈现象的关键。 此外，我们将在果蝇中启动一个新的方向，以扩展我们的 SREBP途径的遗传分析， 胆固醇在培养的果蝇细胞中，我们的目标是鉴定代谢物 调节果蝇中SREBP活性的基因， 这条路。苍蝇体内缺乏胆固醇合成， 研究SREBP信号转导的非固醇代谢产物的调节， 没有观察到的甾醇介导的调节的并发症， 哺乳动物系统我们将在体内研究SREBP通路， 缺乏SREBP、S1 P、S2 P和SCAP的果蝇。这些变种人能让我们 识别和表征与功能丧失相关的表型 胆固醇反馈不正常的动物中的SREBP途径 控制机制。一旦这些表型已知，我们将使用遗传 果蝇筛选SREBP相关基因的独特策略 在哺乳动物系统中难以识别的途径。

DESCRIPTION: (provided by applicant) During the past four years, we have used mutant mammalian cells to clone three new genes essential to the SREBP pathway that regulate cholesterol and fatty acid metabolism in mammalian cells. These three genes are SREBP cleavage-activating protein (SCAP), Site-1 protease (S1P), and Site-2 protease (S2P). The mutant cells have also proven crucial to our analysis of the function of these loci. We will continue to use the tools of mammalian cell genetics to pursue the hypothesis that additional essential genes regulating the SREBP signaling pathway remain to be discovered. In particular, we seek to identify the gene encoding a putative "ER retention protein" that is required for the sterol-regulated movement of the SCAP/SREBP complex between the endoplasmic reticulum (ER) and the Golgi. This protein may hold the key to the cholesterol feedback phenomenon. In addition, we will initiate a new direction, in Drosophila, to extend our genetic analysis of the SREBP pathway to an organism that cannot synthesize cholesterol. In cultured Drosophila cells, our aim is to identify metabolites that regulate SREBP activity in flies, as well as to identify the gene targets of this pathway. The lack of cholesterol synthesis in flies will allow us to study the regulation of SREBP signaling by non-sterol metabolites in the absence of the complications of the sterol-mediated regulation observed in mammalian systems. We will study the SREBP pathway in vivo by creating mutant flies lacking SREBP, S1P, S2P, and SCAP. These mutants will enable us to identify and characterize phenotypes associated with the loss of function of the SREBP pathway in an animal in which cholesterol feedback is not a normal control mechanism. Once such phenotypes are known, we will use genetic strategies unique to Drosophila to screen for genes involved in the SREBP pathway that would otherwise be difficult to identify in the mammalian system.