RNA POLYMERASE AND BACTERIAL DIFFERENTIATION

RNA 聚合酶和细菌分化

• 批准号: 6519754
• 负责人: Charles P. Moran
• 金额: $ 34.01万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519754
• 关键词: Bacillus subtilis; DNA directed RNA polymerase; bacterial genetics; biological signal transduction; genetic regulatory element; immunoelectron microscopy; immunofluorescence technique; microorganism growth; transcription factor

As the bacterium Bacillus subtilis differentiates from the vegetative form into a dormant endospore, complex morphological changes occur that require the expression of many genes. During the process, new RNA polymerase sigma subunits appear, displacing one another and conferring on the RNA polymerase different specificities for the recognition of different classes of promoters. The activity of each sigma factor appears to be regulated in response to morphological cues that signal the completion of specific stages in the differentiation process, and in several instances intercellular signaling between the forespore and mother cell is required. Elucidation of the mechanisms that synchronize morphological transformations and gene expression in Bacillus subtilis may lead to the discovery of novel mechanisms that regulate gene expression in a wide variety of microorganisms. Therefore, we will study the mechanisms that synchronize the activation of two different sigma factors with two different morphological transformations. SapA protein acts in the early stage of spore coat assembly and may be proteolytically processed by the same machinery that processes pro- to activate thereby coordinating the activation of sigma K with the completion of the foundation for the spore coat. We will test this hypothesis, and determine how SapA is targeted to the interface region between the undercoat and cortex peptidoglycan. Forespore-specific transcription is initiated by sigma F-RNA polymerase, and results in the forespore-specific production of sigmaG. However, transcription of spoIIIG, the structural gene for , is delayed relative to other sigmaF-dependent genes, and requires an unidentified intercellular signal. We will characterize this mechanism of intercellular regulation by identifying cis-acting elements in the spoIIIG promoter, and trans-acting factors that regulate spoIIIG promoter activity. sigmaG accumulates after transcription of spoIIIG but does not become fully active until engulfment of the forespore is completed. We will study the function of two proteins that appear to affect sigmaG activation. Transcription of the orfD gene, which encodes one of these proteins, is directed from a promoter unlike any other known to be active during sporulation. Therefore, we will elucidate the mechanism that regulates orfD transcription. Mutations in spoIIIJ prevent sigmaG activation. We will test the hypothesis that spoIIIJ encodes a pheromone-like peptide that plays a role in signaling sigmaG activation.

随着细菌枯草枯草枯草与营养形式区分 休眠的内孢子，复杂的形态变化，需要 许多基因的表达。在此过程中，新的RNA聚合酶Sigma亚基 出现，彼此取代并赋予RNA聚合酶不同 识别不同类别启动子的特异性。这 每个sigma因子的活性似乎都受到调节 形态学提示，表明完成特定阶段 分化过程，在某些情况下，细胞间信号传导 需要在前孔和母细胞之间。阐明 同步形态转化和基因表达的机制 在枯草芽孢杆菌中可能导致发现新机制 调节多种微生物中的基因表达。因此，我们 将研究同步两个不同的激活的机制 Sigma因子具有两个不同的形态转化。 SAPA蛋白在孢子外套组件的早期起作用，可能是 通过处理可激活的相同机械处理的蛋白水解处理 从而协调Sigma K的激活与完成 孢子外套的基础。我们将检验这一假设，并确定如何 SAPA针对底漆和皮质之间的接口区域 肽聚糖。 Sigma F-RNA启动了前孔特异性转录 聚合酶，并导致特定于sigmag的前孔特异性产生。 但是，结构基因的spoiiig转录延迟 相对于其他依赖SIGMAF的基因，需要一个身份不明的 细胞间信号。我们将表征这种细胞间的机制 通过识别spoiiig启动子中的顺式作用元件，并 调节spoiiig启动子活性的跨作用因子。西格马格 转录后累积，但没有完全活跃 直到吞没前孔为止。我们将研究 似乎影响Sigmag激活的两种蛋白质。 ORFD的转录 编码这些蛋白质之一的基因是从启动子引导的 任何已知在孢子形成过程中活跃的任何其他人。因此，我们将阐明 调节ORFD转录的机制。 Spoiiij的突变预防 Sigmag激活。我们将测试Spoiiij编码A的假设 信息素样肽在信号sigmag激活中起作用。