ISOLATION OF EARLY SPORULATION GENES

枯草芽孢杆菌中的孢子形成是一种精心的适应， 生活在营养不良的环境中。 这个过程可以 分为两个监管阶段。 初始阶段可以是 被视为对环境恶化的直接反应， 导致一小部分基因的表达，其中一些是 可能参与开启其他基因;这一阶段是 随后是一段长时间的差异基因表达， 在时间和空间上是有规律的。 后一阶段的规定为 至少部分是由于RNA的sigma因子组分的变化 聚合酶;在某种程度上，这种调节可以被视为对 形态学线索。 在初始阶段， 明白 这方面问题的主要线索 孢子形成的起始与 细胞内GTP浓度下降， 某些突变似乎定义了基因， 参与这项规定。 核心问题可以被框定在 如下：a）GTP下降诱导 孢子形成B）最早的监管顺序是什么 事件？以及，c）假定的调节基因前体的作用是什么？ 管道？本提案旨在通过以下方式解决这些问题： 识别一类在人类早期表达的基因， 孢子形成，分析这些基因的调控， 确定负责其调节的蛋白质。 一 互补项目涉及基因的调控， 乌头酸酶和其他碳调节基因。 由于碳 限制是诱导孢子形成的重要因素， 了解某些基因对特定基因应答的机制， 可用碳源可能提供重要的 关于早期孢子形成事件的信息。 的具体目标 建议是：（1）创建富集了 早期孢子形成序列，并利用它们来分离和研究早期 产孢基因;（2）顺乌头酸酶基因调控分析 通过鉴定启动子区域和蛋白质中的调节位点， 与这些网站相互作用;（3）分离和研究一类 当碳源变得有限时， （4）确定一种机制，通过这种机制， GTP池导致早期孢子形成基因表达。

Spore formation in Bacillus subtilis is an elaborate adaptation to life in a poor nutritional environment. This process can be divided into two regulatory phases. The initiation phase can be viewed as the immediate response to a deteriorating environment, leading to expression of a small set of genes, some of which are likely to be involved in turning on other genes; this phase is followed by a prolonged period of differential gene expression that is regulated in time and space. This latter phase is regulated at least in part by changes in the sigma factor component of RNA polymerase; to some extent this regulation can be seen to respond to morphological cues. The initiation phase is much less well understood. The major clues relevant to this aspect of the problem are a strict correlation between initiation of sporulation and a drop in the intracellular concentration of GTP and the existence of certain mutations that appear to define genes whose products are involved in this regulation. The central questions can be framed as follows: a) What is the mechanism by which a drop in GTP induces sporulation? b) What is the order of the earliest regulatory events? and, c) What are the roles of putative regulatory gene pro- ducts? This proposal seeks to address these questions by identifying a class of genes expressed at very early times of sporulation, analyzing the regulation of those genes, and identifying the proteins responsible for their regulation. A complementary project deals with regulation of the gene for aconitase and other carbon-regulated genes. Since carbon limitation is an important factor in inducing sporulation, a clear understanding of the mechanism by which certain genes respond to the available carbon source is likely to provide important information about early sporulation events. The specific aims of the proposal are: (1) Create cDNA probes that are enriched for early sporulation sequences and use them to isolate and study early sporulation genes; (2) analyze the regulation of the aconitase gene by identifying regulatory sites in the promoter region and proteins that interact with those sites; (3) isolate and study a class of genes that is turned on when the carbon source becomes limiting for growth; and, (4) determine the mechanism by which a change in the pool of GTP leads to early sporulation gene expression.