YEAST PEPTIDE HORMONE SYNTHESIS AND SIGNAL TRANSDUCTION

这项研究的目的是了解精确的分子 肽激素的生物合成和 肽类激素的作用机制。 分泌型生物活性物质 肽（肽激素，生长因子，神经调节肽， 潮汐）是细胞间相互作用不可或缺的因素 控制胚胎发育和协调， 成年人生活功能的整合。 许多人类 疾病与生产不足（或过度）有关 调节肽，或无法正确响应 这样的信号。 即使是单细胞真核微生物 酿酒酵母（面包酵母）分泌并响应 肽激素（“交配信息素”）-因为精辟的遗传 并且可以在酵母细胞中进行生物化学研究， 特别是那些利用重组DNA的研究， 酵母中激素生物合成和信号转导可能提供 对理解疾病分子基础的有用见解 影响人类神经内分泌系统的物质 提出了四个具体的调查领域：（1） 细胞类型特异性基因表达的分子基础将是 通过检查MF a1的转录调节来研究 基因（编码一种前体，前原-a-因子， 交配信息素）-遗传和生化实验是 建议进一步定义顺式作用位点和 负责控制该基因的反式作用因子， 以及探索一种特殊的“锌指”的作用- 含有转录因子（STE 5基因产物）。 (2)的 前体成熟的酶基础，位点包括 将通过测定 酵母前体裂解酶的三维结构 (KEX2基因产物），并通过使用探针 基于这个酵母基因分离出它的哺乳动物同源物。 （三） 质膜受体如何作为配体触发的 分子开关及其功能在过程中如何调节 脱敏作用将使用克隆的α因子来阐明， 受体基因（STE 2）、其偶联的G α亚基（GPA 1基因 产物），以及迄今为止的调节因子（SST 2基因产物）。 未知函数 (4)激素诱导基因转录 将通过遗传和生化实验进行研究， 来鉴定和表征与这些蛋白质相互作用的蛋白质因子， 上游信息素响应元件（PRE）。

The objective of this research is to learn the precise molecular details of both the biosynthesis of peptide hormones and the mechanism of action of peptide hormones. Secreted bioactive peptides (peptide hormones, growth factors, neuroregulatory pep- tides) are indispensable agents of the intercellular interactions that control both embryonic development and the coordination and integration of life functions in the adult. Numerous human diseases are associated with the under- (or over-) production of regulatory peptides, or with the inability to respond properly to such signals. Even the unicellular eukaryotic microorganism Saccharomyces cerevisiae (baker's yeast) secretes and responds to peptide hormones ("mating pheromones")- Because incisive genetic and biochemical studies can be performed in yeast cells, particularly those that utilize recombinant DNA, study of peptide hormone biogenesis and signal transduction in yeast may provide useful insights for understanding the molecular basis of diseases that affect the human neuroendocrine system. Four specific areas of investigation are proposed: (1) The molecular basis of cell type-specific gene expression will be studied by examining the transcriptional regulation of the MF a1 gene (which encodes a precursor, prepro-a-factor, of one of the mating pheromones)- Genetic and biochemical experiments are proposed for further defining both the cis-acting sites and the trans-acting factors responsible for the control of this gene, and for exploring the role of a particular "zinc finger"- containing transcription factor (STE5 gene product). (2) The enzymic basis of pre= cursor maturation at sites comprised of pairs of basic residues will be explored by determination of the three-dimensional structure of a yeast precursor cleaving enzyme (KEX2 gene product) with this specificity and by using probes based on this yeast gene to isolate its mammalian homolog. (3) How a plasma membrane receptor acts as a ligand-triggered molecular switch and how its function is regulated during desensitization will be elucidated using the cloned alpha-factor receptor gene (STE2), its coupled G a subunit (GPAl gene product), and a regulatory factor (SST2 gene product) of as yet unknown function. (4) Hormonal induction of gene transcription will be studied by genetic and biochemical experiments designed to identify and characterize the protein factors that interact with an upstream pheromone-response element (PRE).