Protein/Protein Interactions in Prokaryotic Gene Control

描述(申请人提供)：细菌中的转录依赖于从细菌到人类保守的多亚基RNA聚合酶(RNAP)。原核生物系统的研究已经定义了基本的转录周期，为研究所有生物的转录提供了一个机制框架。由于RNAP是基因调控的主要靶点，深入了解其结构和功能对于阐明控制基因表达的各种调控机制至关重要。对细菌系统中转录装置及其调控的研究产生的原理继续推动控制微生物病原体的新策略的开发，以及对人类发育和疾病过程中许多基于转录的过程的研究。为了在细菌中启动转录，精通催化的核心酶必须与？形成全酶的因子。除了角色之外？转录启动因子，多年来一直被深入研究，越来越多的证据表明？因子可以参与起始下游的事件，而且，调节器可以在延伸过程中靶向RNAP全酶。这已经为噬菌体的Q抗终止子蛋白建立，它在依赖于？的早期伸长暂停时与RNAP全酶结合。这项研究的第一个目的是研究Q在伸长早期与RNAP全酶的相互作用，以了解Q进入转录复合体并改变其行为的专门途径的性质。这项研究的第二个目的是研究？/core相互作用以一种特定阶段的方式影响RNAP的功能特性，调节启动子逃逸和早期伸长暂停。这项拟议研究的第三个目标是调查一个？作为转录抗终止子的因子是如何存在的？在成熟的伸长过程中，复合体可能受到调控。综上所述，目标2和目标3中提出的实验将使我们更深入地理解？转录周期中的所有因子。

DESCRIPTION (provided by applicant): Transcription in bacteria depends on a multi-subunit RNA polymerase (RNAP) that is conserved from bacteria to man. The study of prokaryotic systems has defined the basic transcription cycle, providing a mechanistic framework for the study of transcription in all organisms. Because RNAP is the primary target of gene regulation, an in depth understanding of its structure and function is essential for elucidating the variety of regulatory mechanisms that control gene expression. The principles that emerge from investigations of the transcription apparatus and its regulation in bacterial systems continue to drive both the development of new strategies to control microbial pathogens and the study of the many transcription-based processes that underlie human development and disease processes. For transcription to initiate in bacteria, the catalytically proficient core enzyme must combine with ? factor to form the holoenzyme. In addition to the roles of ? factors in transcription initiation, which have been intensively investigated over many years, accumulating evidence indicates that ? factors can participate in events downstream of initiation and, moreover, that regulators can target the RNAP holoenzyme during elongation. This has been established for the Q antiterminator protein of bacteriophage ?, which engages the RNAP holoenzyme at a ?-dependent early elongation pause. The first aim of the proposed research is to investigate Q's interactions with the RNAP holoenzyme during early elongation to understand the nature of the specialized pathway by which Q gains access to and alters the behavior of the transcription complex. The second aim of the proposed research is to investigate a ?/core interaction that influences the functional properties of RNAP in a stage-specific manner, modulating both promoter escape and early elongation pausing. The third aim of the proposed research is to investigate an unexpected role for a ? factor as a transcription antiterminator and to investigate how the presence of ? in mature elongation complexes might be regulated. Together, the experiments proposed in Aims 2 and 3 will lead to a deeper understanding of the dynamic roles played by ? factors throughout the transcription cycle.