RNA POLYMERASE AND BACTERIAL DIFFERENTIATION

随着枯草芽孢杆菌从繁殖体分化为 休眠的内孢子，发生复杂的形态变化，需要 许多基因的表达。在这个过程中，新的RNA聚合酶西格玛亚基 出现、置换和赋予RNA聚合酶不同 不同类别发起人识别的特殊性。这个 每个Sigma因子的活性似乎都受到调节，以响应 形态上的提示，标志着 分化过程，在几种情况下细胞间信号 前孔和母细胞之间是必需的。澄清： 形态转化和基因表达同步的机制 可能导致发现新的机制，即 调节多种微生物中的基因表达。因此，我们 我将研究使两个不同的 具有两种不同形态转换的西格玛因子。 SapA蛋白在孢子壳组装的早期阶段起作用，可能是 由处理PRO-TO激活的相同机器进行蛋白质分解处理 从而协调Sigma K的激活与完成 孢子被的根基。我们将检验这一假设，并确定如何 Sapa定位于底毛和皮层之间的界面区域。 多肽聚糖。前孢子特异转录由Sigma F-RNA启动 聚合酶，并导致前孔特异性产生SigmaG。 然而，SpoIIIG结构基因的转录被推迟 相对于其他依赖sigmaF的基因，并且需要一个未知的 细胞间信号。我们将描述这种细胞间的机制。 通过识别SPIIIG启动子中的顺式作用元件进行调控，以及 调节spIIIG启动子活性的反式作用因子。西格玛 SpIIIG转录后积聚，但未完全激活 直到前孔完全被吞没。我们将研究它的功能 两种似乎影响SigmaG激活的蛋白质。OrfD的转录 编码其中一种蛋白质的基因是由启动子引导的，不同于 任何其他已知的在产孢期活跃的细菌。因此，我们将澄清 调节orfD转录的机制。SPIRIJ基因突变可预防 SigmaG激活。我们将测试SPIIIJ编码一个 信息素样肽，在信号转导SigmaG激活中起作用。

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.