SRF OPERON--REGULATION AND ROLE IN GENETIC COMPETENCE

细菌拥有复杂的信号转导网络，控制着 细胞对环境变化的反应。在枯草芽孢杆菌中， 网络控制在限制增长时激活的进程 遇到了环境。感测高电池区状况的系统 密度和饥饿共同激活SRF的表达 操纵子，编码酶复合体，催化 脂肽类抗生素、表面活性蛋白和编码基因调控因子 能力，这是表达基因所必需的 在DNA导入中的作用。对SRF调节和功能的研究将 加深我们对细菌如何调节细菌生产的了解 毒素和抗生素，以及基因转化的过程，这 是细菌获得赋予抗药性的基因的一种方式。突变 改变SRF表达和营养依赖的调节 孢子形成，称为GGR(葡萄糖-谷氨酰胺依赖调节)，结果 在浓度升高的Sigma-H中，由spOH编码，并需要 信息素CSF(能力刺激因子)的产生 激活SRF转录。GGR突变也会导致CRS (抗分解代谢产孢子)表型。GGR的轨迹将会是 分离和鉴定以确定它们在细胞密度中的作用-和 SRF表达的营养调控。位于和内的coms基因 框外与srfB基因的SRF操纵子，是受 与控制SRF转录的调控分开的调控 入会仪式。这一规定要求sinR，它也在 细胞决定是否进行产孢子或能力发育。这个 参与SINR依赖控制的SRF区域(S)将是 已确认身份。其他专门影响coms表达的突变将 被分离出来，并通过核苷酸序列测定进行表征，并通过 将突变引入sinR突变体或过度表达的细胞 SINR。细胞内位置和细胞类型分布(有能力 或非胜任小区)将使用反COMS来确定 抗体。COMS的结构及其在控制疾病中的可能作用 Degu的活性(一种类似于反应调节蛋白的蛋白，在 降解酶的产量和能力)，ComK(The 转录激活因子能力基因)或MBA和B(同源物 ATP依赖的蛋白水解酶和热休克蛋白，以及负调控因子 将通过突变分析和蛋白质-蛋白质来研究 交联剂实验。编码COMS的基因的鉴定- 结合蛋白将使用酵母双杂交系统进行分离。

Bacteria possess complex signal transduction networks that govern the cells' response to environmental changes. In Bacillus subtilis, such a network controls processes that are activated when a growth-limiting environment is encountered. Systems which sense conditions of high cell density and starvation converge to activate the expression of the srf operon, encoding the enzyme complex that catalyzes the biosynthesis of the lipopeptide antibiotic, surfactin, and encoding a regulator of genetic competence, ComS, which is required for the expression of genes that function in DNA import. Studies of srf regulation and function will enhance our understanding of how bacteria regulate the production of toxins and antibiotics, and the process of genetic transformation, which is one way bacteria acquire genes that confer drug resistance. Mutations that alter the nutrition-dependent regulation of srf expression and sporulation, called ggr (glucose-glutamine-dependent regulation), result in an elevated concentration of sigma-H, encoded by spoOH and required for the production of the pheromone Csf (competence stimulating factor) which activates srf transcription. The ggr mutations also confer a Crs (catabolite resistant sporulation) phenotype. The ggr loci will be isolated and characterized to determine their roles in cell density- and nutritional control of srf expression. The comS gene, located within and out-of-frame with the srfB gene of the srf operon, is subject to regulation that is separate from that which controls srf transcription initiation. This regulation requires sinR, which also functions in the cell's decision to undergo sporulation or competence development. The region(s) of srf that functions in sinR- dependent control will be identified. Other mutations that effect specifically comS expression will be isolated and characterized by nucleotide sequence determination, and by introducing the mutations into sinR mutants or cells that overexpress sinR. The intracellular location and the cell type distribution (competent or non-competent cell) of ComS will be determined using anti-ComS antibody. The structure of ComS and its possible role in controlling the activity of DegU (a response regulator-like protein that functions in the contor of degradative enzyme production and competence), ComK (the transcriptional activator of competence genes) or MBA and B (homologues of ATP-dependent proteases and heat shock proteins, and negative regulators of ComK) will be investigated by mutational analysis and protein-protein crosslinking experiments. The identification of genes that encode ComS- binding proteins will be isolated using the yeast two-hybrid system.