Molecular Genetics of Bacillus subtilis RNA Polymerase

描述(申请人提供)：接触不同种类的细菌 生长限制压力诱导合成一组共同的蛋白质，这些蛋白质 提供广泛的保护，抵御未来的致命挑战。这种普遍的压力 响应增强了在自然环境中新鲜和加工后的生存 食物，以及某些致病的相互作用。枯草芽孢杆菌和 相关的革兰氏阳性病原体，这种反应由SigmaB控制 转录因子。SigmaB功能的丧失会导致对 多重应激，包括酸、热、渗透和氧化应激。我们的 长期目标是利用枯草芽孢杆菌作为 一个模型，从检测不同应力的传感器开始， 通过传递这一信息的信号转导网络延伸 到sigmaB，并以200个或更多基因的生理作用结束 在sigmaB控制下。在这些区域中，大多数都是关于信号的 转导网络，其功能是通过在 哪种交替蛋白质复合体的形成受丝氨酸和 苏氨酸磷酸化。这个机制看起来很古老，很古老 塑料，在真细菌中广泛存在。在这里它激活了中的sigmaB 对两类压力的反应：(一)能量压力，包括饥饿 对于碳、磷或氧；以及(Ii)环境压力，包括 酸、乙醇、热或盐应激。这两个类别通过以下方式传送到AB 独立的上行信令通路，每个通路以不同的 PP2C磷酸酶的调节及其在两种直接调节因子上的趋同 SigmaB、RsbV抗-a和RsbW抗-a因子。能源部门 由RSBP磷酸酶组成(具有一个对信号重要的PAS结构域) 以及RsbQ，这是一种功能未知的蛋白质，需要信号传递。这个 环境部门至少有九个监管机构，所有人都加入进来激活 RsbU磷酸酶。能量或环境信号如何进入各自的 分支机构未知。同样鲜为人知的是，sigmaB中的基因是如何 调节子有助于抗逆性。使用DNA阵列的实验表明 SigmaB只控制几个具有直接保护功能的基因 而是控制新陈代谢和包膜功能的变化，这可能会赋予 被动抵抗。我们的三个具体目标涉及以下问题： (1)能量压力信号如何激活其网络分支；(2)如何 环境信号是否激活了它们的分支；以及(3)什么是环境信号 新发现的SigmaB调节子成员的生理作用， 尤其是那些可能参与下行信令的？

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?