ISOLATION OF EARLY SPORULATION GENES

枯草芽孢杆菌的孢子形成是对 生活在恶劣的营养环境中。这一过程可以是 分为两个监管阶段。启动阶段可以是 被视为对不断恶化的环境的直接反应， 导致一小部分基因的表达，其中一些是 可能参与启动其他基因；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。后一阶段的规定是 至少部分是由RNA的西格玛因子成分的变化引起的 聚合酶；在某种程度上，可以看到这种调节对 形态上的线索。启动阶段就差得多了。 明白了。与问题的这一方面有关的主要线索 产孢量的启动与一种 细胞内GTP浓度的下降及其存在 某些突变似乎定义了其产物是 参与了这项规定。核心问题可以被框定 A)GTP的下降通过什么机制诱导 产孢子？B)最早的监管机构的顺序是什么 活动？以及，c)假定的调控基因Pro-2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 鉴定一类在非常早期就表达的基因 孢子形成，分析这些基因的调节，以及 确定负责调节它们的蛋白质。一个 补充性项目涉及对基因的调节 乌头酸酶和其他碳调节基因。因为碳 限制是诱导孢子形成的一个重要因素，一个明显的 对某些基因响应的机制的理解 可用的碳源可能会提供重要的 有关早期孢子形成事件的信息。的具体目标 这些建议是：(1)建立富含DNA探针 早期产孢子序列并利用它们进行早期分离和研究 (2)分析乌头酸酶基因的调控。 通过确定启动子区域和蛋白质中的调控位点 与这些站点进行交互；(3)分离并研究一类 当碳源变得受限于 增长；以及，(4)确定变化的机制 GTP池导致产孢子基因的早期表达。

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.