ROLE OF RNA POLYMERASE IN BACTERIAL DIFFERENTIATION

我们的研究计划的总体目标是了解时间和 内生孢子形成过程中基因表达的空间调控 革兰氏阳性菌枯草芽孢杆菌，并了解如何 孢子形成基因的程序化表达被记录在 伴随孢子发生的形态学事件。 中央到一个 这些问题的调查是五个特定的发展，RNA 聚合酶σ因子和几种辅助转录因子， 控制孢子形成基因表达的程序。我们建议 研究sigma因子如何介导启动子识别， σ和辅助转录因子的出现受到调节 在时间和空间上，哪些基因组受每个因子的控制 什么样的反馈机制协调外观或 这些因子的活性与孢子发生过程有关。 我们特别 将”识别启动子识别螺旋之间的接触位点“- 孢子形成σ因子σ H中的10”序列和同源序列中的碱基 启动子，研究sigmaH在早期产孢基因中的作用 表达式，测试sigmaH控制 孢子形成σ因子σ F的基因，鉴定 控制sigmaF并修饰sigmaF的启动子识别特异性， sigmaF，研究sigmaE、sigmaK和转录因子的作用 SpoIIID、spoVP和GerE在孢子外壳基因级联调节中的作用， 研究母细胞重排的机理基础 产生母细胞复合结构基因的染色体 sigma因子sigmaK，研究前蛋白的可能存在 前体sigmaK和测试的假设，“形态” 通过分离允许外壳基因的旁路突变进行偶联 在前孢子基因表达受阻的突变体中表达，最后， 使用免疫电子显微镜定位特定的发育蛋白质 在孢子和孢子形成细胞中。 这些目标涉及以下基本问题： 基因表达时间、空间和形态控制， 常见于许多种类的发育系统，包括复杂的 高等生物的正常和异常发育。

The overall goals of our program of research are to understand temporal and spatial regulation of gene expression during endospore formation in the Gram-positive bacterium Bacillus subtilis and to understand how the programmed expression of sporulation genes is kept in register with the morphological events accompanying sporogenesis. Central to an investigation of these issues are five developmental-specific, RNA polymerase sigma factors and several auxiliary transcription factors that govern the program of sporulation gene expression. We propose to investigate how sigma factors mediate promoter recognition, how the appearance of sigma and auxiliary transcription factors is regulated temporally and spatially, which sets of genes are controlled by each factor and what kinds of feed-back mechanisms coordinate the appearance or activity of the factors with the course of sporogenesis. Specifically, we will" identify contact sites between a recognition helix for promoter "- 10" sequences in the sporulation sigma factor sigmaH and bases in cognate promoter, investigate the role of sigmaH in early sporulation gene expression, test the proposal that sigmaH governs the transcription of the gene for the sporulation sigma factor sigmaF, identify genes under the control of sigmaF and modify the promoter recognition specificity of sigmaF, study the roles of sigmaE, sigmaK and transcription factors SpoIIID, spoVP and GerE in cascade regulation of spore coat genes, investigate the mechanistic basis for a rearrangement in the mother-cell chromosome that generates the composite structural gene for the mother-cell sigma factor sigmaK, investigate the possible existence of a pro-protein precursor to sigmaK and test the hypothesis that the "morphological" coupling by the isolation of bypass mutations that permit coat gene expression in mutants blocked in forespore gene expression, and, finally, use immunoelectron microscopy to localize specific developmental proteins in spores and in sporulating cells. These goals address basic issues of temporal, spatial and morphological control of gene expression that are common to developmental systems of many kinds, including complex systems of norma and abnormal development in higher organisms.