MECHANISM, ACTIVATION AND CONTROL OF RRNA TRANSCRIPTION

描述：核糖体是蛋白质合成的中心成分。 在所有的牢房里。在大肠杆菌中，核糖体RNA合成的速度 决定核糖体合成的速度。多种机制 有助于rRNA的表达。顺式作用序列(UP 元素)和反式作用蛋白(FIS)是高活性的原因 RRNA启动子。此外，至少有两个监管因素，ppGpp 和一个身份不明的反馈调节器，解释了严格的 RRNA转录的控制和生长速度相关的控制， 分别进行了分析。在下一个资助期内，建议进行以下试验 确定已知的激活剂和调节器的机制 影响RNA聚合酶，并确定剩余的效应器 影响rRNA转录。这些研究具有广泛的影响，不是 不仅是为了我们了解细菌中的核糖体合成，而且还 为了我们了解原核生物的基本转录机制 和真核生物。 所涉及的组件之间相互作用的分子细节 在RRN P1启动子的转录激活中(RNAP，UP元件， 和FIS)将被确定。RNAP对UP元件的识别 代表了我们细菌转录图景中的一个新范例。 FIS-RNAP相互作用的研究也很有兴趣，因为FIS- 依赖激活表示激活类，不同于那些 具有先前特征的。因此，关键问题的识别 RNAP中影响UP元素和FIS利用的残留物及其 UP元件共识序列的开发应该是主要的 对我们理解抄写的贡献。的潜在作用 RNAP的α和西格玛亚基都将被研究。两者都有 描述了解决这些问题的遗传和生物化学方法。 多个监管机构之间的补偿效应掩盖了 能够确定各个系统对特定系统的响应 影响rRNA转录的环境信号。顺位代理 影响rrnB转录的所有已知机制的靶点 现在已经确定了P1。通过利用启动子突变 选择性地消除启动子对FIS、ppGpp或反馈的响应，它 应该可以确定依赖于FIS的贡献 在特定时间对rRNA表达的激活，其机制 PpGpp对转录的抑制，以及该基因的分子同一性 反馈调节器。

DESCRIPTION: The ribosome is the central component of protein synthesis in all cells. In E. coli, the rate of ribosomal RNA synthesis determines the rate of ribosome synthesis. Multiple mechanisms contribute to the expression of rRNA. A cis-acting sequence (the UP Element) and a trans-acting protein (FIS) account for the high activity of rRNA promoters. In addition, at least two regulatory factors, ppGpp and an unidentified feedback regulator, account for the stringent control and growth rate dependent control of rRNA transcription, respectively. In the next funding period, experiments are proposed to determine the mechanism by which the known activators and regulators affect RNA polymerase and to identify the remaining effectors that influence rRNA transcription. These studies have broad implications not only for our understanding of ribosome synthesis in bacteria, but also for our understanding of basic transcription mechanisms in prokaryotes and eukaryotes. The molecular details of the interactions between the components involved in transcription activation of rrn P1 promoters (RNAP, the UP Element, and FIS) will be determined. Recognition of the UP Element by RNAP represents a new paradigm in our picture of bacterial transcription. The study of FIS-RNAP interactions is also of interest, since FIS- dependent activation represents an activation class unlike those characterized previously. Thus, the identification of the critical residues in RNAP affecting UP Element and FIS utilization and the development of an UP Element consensus sequence should be major contributions to our understanding of transcription. Potential roles of both the alpha and sigma subunits of RNAP will be investigated. Both genetic and biochemical approaches to these problems are described. Compensating effects between multiple regulators have obscured the ability to determine the responses of individual systems to specific environmental signals affecting rRNA transcription. The cis-acting targets for all the known mechanisms affecting transcription from rrnB P1 have now been identified. By utilizing promoter mutations which selectively eliminate promoter responses to FIS, ppGpp, or feedback, it should be possible to determine the contribution of FIS-dependent activation to rRNA expression at specific times, the mechanism of transcription inhibition by ppGpp, and the molecular identity of the feedback regulator.