GENETICS OF YEAST PHEROMONE SIGNAL TRANSDUCTION

信号转导是一个重要的生物过程，通过它 来自细胞外刺激的信息被传递给细胞， 从而导致细胞生理学的变化。的长期目标是 这一建议是在分子水平上对这种机制的描述 参与传递由信息素产生的信号 酵母交配反应。酵母遗传学将被用来阐明 被认为参与这一过程的基因的作用并识别新的 基因通过抑制子分析。 单倍体酵母细胞通过两种细胞类型对交配信息素做出反应- 与异源三聚体G蛋白相连的特定受体。在酵母中， 与大多数其他系统不同，G蛋白的Betagamma复合体出现 为了在从阿尔法亚单位释放后传播信号 与被占领的受体相互作用。发生的分子事件 G蛋白下游并不被很好地理解，并构成一种 重要的研究领域。 这项提议的一个具体目的是研究基因的功能 被分离出来作为一种温度敏感的多拷贝抑制因子 Gbeta亚基，以及与之密切相关的基因的功能。这些 基因形成了一个基本的冗余集合，因为它们中的一个 是细胞存活所必需的。对这些表达方式的分析 基因和当它们不被转录时发生的缺陷将 要承担的责任。包含每个基因的可诱导版本的构建体 将为此目的而创建，还将用于隔离 克服这两种基因缺失所造成的致命性的抑制子 产品。特异性缺陷的抑制基因的等位基因 在交配中也会被隔离。第二个目标是识别蛋白质 与Gbeta亚基相互作用，这是一种基因技术 分离相互作用的基因产物。最后一个目标是 受体介导的脱敏途径的特征 阻止信号在Galpha亚单位下游的传输。 突变将在受体基因的两个区域被分离出来 参与这一功能和其他基因，这些基因在 脱敏途径。 从这些研究中获得的信息将为 哺乳动物G蛋白介导的信号通路控制 对多种刺激的反应，包括荷尔蒙， 神经递质、儿茶酚胺和光。

Signal transduction is an important biological process by which information from extracellular stimuli is communicated to cells, resulting in changes in cellular physiology. The long-term objective of this proposal is a description at the molecular level of the mechanisms involved in transmission of the signal generated by pheromone in the yeast mating response. Yeast genetics will be used to elucidate the roles of genes thought to be involved in this process and to identify new genes through suppressor analysis. Haploid yeast cells respond to mating pheromones via two cell type- specific receptors linked to a heterotrimeric G protein. In yeast, unlike most other systems, the betagamma complex of the G protein appears to propagate the signal after release from the alpha subunit due to interaction with occupied receptor. The molecular events that take place downstream of the G protein are not well understood and constitute an important area for study. A specific aim of this proposal is to investigate the function of a gene that was isolated as a multicopy suppressor of a temperature sensitive Gbeta subunit, as well as the function of a closely-related gene. These genes form an essential redundant set because one or the other of them is required for cell viability. Analysis of the expression of these genes and of the defect that occurs when they are not transcribed will be undertaken. Constructs containing an inducible version of each gene will be created for this purpose and will also be used to isolate suppressors that overcome the lethality caused by the lack of both gene products. Alleles of the suppressor gene that are specifically defective in mating will be isolated as well. A second aim is to identify proteins that interact with the Gbeta subunits, a genetic technique for the isolation of interacting gene products. A final aim is the characterization of a receptor-mediated desensitization pathway that blocks transmission of the signal downstream of the Galpha subunit. Mutations will be isolated both in regions of the receptor gene that are involved in this function and in other genes that act downstream in the desensitization pathway. Information gained from these studies will provide insights into mammalian G protein-mediated signalling pathways which control the response to a number of diverse stimuli, including hormones, neurotransmitters, catecholamines, and light.