NEW YEAST MUTANTS IN POSTGOLGI TRANSPORT

以前的遗传筛查已经鉴定出酵母分泌突变体 在分泌途径的不同点上阻断蛋白质的运输。而当 这些突变体很可能会阻止所有货物的运输，有两类 高尔基体后的囊泡将独特的货物运输到质膜上 是最近才被定性的。这项提议旨在分离新的突变体。 这些囊泡物种中只有一种的运输受阻。一 策略涉及一种选择方案，在该方案中，分泌块将 让细胞生长。虽然此方法很可能只识别非 必要的基因，使用一种选择作为初始步骤应该大大 促进突变体的分离。第二种筛查使用K/28杀手毒素作为 一种用于识别Essential条件突变的分泌型标记 分泌K/28和其他途径中货物所需的基因 运输这种毒素。 更好地理解囊泡介导的转运机制 从高尔基体到质膜将需要鉴定 这一过程中涉及的关键组件，以及对 在建议的筛选中分离出的突变体应该对此有很大的贡献 结束。这些突变体，以及一种新的酵母菌体外萌发试验 晚期分泌性囊泡形成的生化分析 为后续的生化和遗传学研究提供强大的工具。

Previous genetic screens have identified yeast secretory mutants have block protein traffic at various points along the secretory pathway. While these mutants most likely block the transport of all cargo, two classes of post-Golgi vesicles transporting unique cargo to the plasma membrane have been recently characterized. This proposal aims to isolate new mutants blocked in the transport of only one of these vesicle species. One strategy involves a selection scheme in which a secretory block would allow cells to grow. While this method will most likely identify only non- essential genes, the use of a selection as an initial step should greatly facilitate mutant isolation. A second screen utilizes K/28 killer toxin as a secretory marker for identifying conditional mutations in essential genes required for the secretion of K/28 and other cargo in the pathway transporting this toxin. A better understanding of the mechanisms of vesicle-mediated transport from the Golgi to the plasma membrane will require the identification of the key components involved in this process, and characterization of the mutants isolated in the proposed screens should greatly contribute to this end. These mutants, as well as a new in vitro budding assay in yeast for the biochemical analysis of the formation of late secretory vesicles, will provide powerful tools for subsequent biochemical and genetic studies.