Molecular Genetics of Bacillus subtilis RNA Polymerase

描述（由申请人提供）：细菌暴露于多种 限制生长的压力诱导一组共同的蛋白质的合成， 为未来的致命挑战提供了广泛的保护。这种普遍的压力 反应提高了在自然环境中的生存，在新鲜和加工 食物，以及某些致病相互作用。在枯草芽孢杆菌和 相关革兰氏阳性病原体，这种反应由sigmaB控制 转录因子sigmaB功能丧失导致对以下物质的敏感性增加： 多种应激，包括酸、热、渗透和氧化应激。我们 长期目标是了解使用枯草芽孢杆菌作为 一个模型，从检测不同压力的传感器开始， 通过信号传导网络传递信息 到sigmaB，最后是200个或更多基因的生理作用， 在sigmaB控制下。在这些区域中，大多数都知道信号 转导网络，其功能是通过“伙伴转换”机制， 所述交替蛋白质复合物的形成由丝氨酸控制， 苏氨酸磷酸化这种机制似乎是非常古老的，非常 塑料，并广泛存在于真细菌中。这里它激活了sigmaB 对两类压力的反应：（一）能量压力，包括饥饿 碳、磷酸盐或氧;以及（ii）环境压力，包括 酸、乙醇、热或盐胁迫。这两个类通过以下方式传递给aB： 独立的上游信号通路，每个通路以不同的 调节的PP 2C磷酸酶，并聚集在两个直接调节因子上， σ B、RsbV抗-抗-α和RsbW抗-α因子。能源分支 由RsbP磷酸酶组成（具有对信号传导重要的PAS结构域） 和RsbQ，一种信号传导所需的未知功能蛋白。的 环境分支至少有九个监管机构，所有这些机构都加入了环境管理体系， RsbU磷酸酶。能量或环境信号如何进入它们各自的 branches未知同样知之甚少的是sigmaB中的基因是如何 调节子有助于抗应激。使用DNA阵列的实验表明 sigmaB只控制少数具有直接保护功能的基因， 相反，它控制着新陈代谢和包膜功能的变化， 消极抵抗我们的三个具体目标涉及以下问题： (1)能量压力信号是如何激活它们的网络分支的;（2）如何 环境信号是否激活它们的分支;（3） 新鉴定的sigmaB调节子成员的生理作用， 特别是那些可能参与下游信号传导的？

DESCRIPTION (provided by applicant): Exposure of bacteria to diverse growth-limiting stresses induces the synthesis of a common set of proteins that provides broad protection against future lethal challenges. This general stress response enhances survival in the natural environment, in fresh and processed foods, and in certain pathogenic interactions. Among Bacillus subtilis and related Gram positive pathogens, this response is governed by the sigmaB transcription factor. Loss of sigmaB function causes increased sensitivity to multiple stresses, including acid, heat, osmotic, and oxidative stress. Our long term objective is to understand this response using Bacillus subtilis as a model, beginning with the sensors that detect the different stresses, extending through the signal transduction network that conveys this information to sigmaB, and ending with the physiological role of the 200 or more genes under sigmaB control. Of these areas, most is known about the signal transduction network, which functions by a 'partner switching" mechanism in which formation of alternate protein complexes is controlled by serine and threonine phosphoiylation. This mechanism apears to be very ancient, very plastic, and widespread among the eubacteria. Here it activates sigmaB in response to two classes of stresses: (i) energy stress, including starvation for carbon, phosphate, or oxygen; and (ii) environmental stress, including acid, ethanol, heat, or salt stress. These two classes are conveyed to aB by independent upstream signaling pathways, each terminating with a differentially regulated PP2C phosphatase and converging on the two direct regulators of sigmaB, the RsbV anti-anti-a and the RsbW anti-a factor. The energy branch consists of the RsbP phosphatase (with a PAS domain important for signaling) and RsbQ, a protein of unknown function required for signaling. The environmental branch has at least nine regulators, all joining to activate the RsbU phosphatase. How energy or environmental signals enter their respective branches is unknown. Also poorly understood is how the genes in the sigmaB regulon contribute to stress resistance. Experiments using DNA arrays indicate that sigmaB controls only a few genes with a direct protective function and instead governs changes in metabolism and envelope function which may confer a passive resistance. Our three specific aims address the following questions: (1) How do energy stress signals activate their branch of the network; (2) How do environmental signals activate their branch; and (3) What are the physiological roles of newly identified members of the sigmaB regulon, particularly those that may be involved in downstream signaling?