ROLE OF RNA POLYMERASE IN BACTERIAL DIFFERENTIATION

我们研究计划的总体目标是理解时间和 小麦内孢子形成过程中基因表达的空间调控 革兰氏阳性杆菌枯草芽孢杆菌和了解 产孢子基因的程序化表达与 伴随着孢子发生的形态事件。中心到 这些问题的研究有五个特定的发育问题，RNA 聚合酶西格玛因子和几种辅助转录因子 控制产孢子基因的表达程序。我们建议 研究西格玛因子如何介导启动子识别，如何 Sigma和辅助转录因子的出现受到调控 在时间和空间上，哪组基因受每个因素控制 以及什么样的反馈机制协调了外观或 这些因子的活性与孢子发生的过程有关。具体来说，我们 将“确定启动子的识别螺旋之间的接触点”- 产孢斯格玛因子SigmaH中的10“序列和同源序列中的碱基 启动子，研究SigmaH在早期产孢子基因中的作用 表达，测试sigmaH调控转录的建议 芽胞形成西格玛因子SigmaF的基因，鉴定基因 调控SigmaF并改变其启动子识别特异性 SigmaF，研究SigmaE、SigmaK和转录因子的作用 SpoIIid、SpoVP和Gere在孢子皮基因级联调控中的作用 探讨母细胞重排的机制基础 为母细胞产生复合结构基因的染色体 Sigma因子SigmaK，研究一种前蛋白的可能存在 SigmaK的前身，并检验“形态”的假设 通过分离允许外壳基因的旁路突变进行耦合 在前孔基因表达受阻的突变体中的表达，最后， 用免疫电子显微镜定位特定的发育蛋白 在孢子和产孢细胞中。这些目标涉及以下基本问题 基因表达的时间、空间和形态控制 在许多类型的发育系统中共有的，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.