Protein/Protein Interactions in Prokaryotic Gene Control

描述（由申请人提供）：细菌的转录依赖于多亚基RNA聚合酶（RNAP），该酶从细菌到人类都是保守的。对原核生物系统的研究已经确定了基本的转录周期，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，因此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。从对细菌系统中转录装置及其调控的研究中得出的原理继续推动着控制微生物病原体的新策略的发展，以及对人类发育和疾病过程中基于转录的许多过程的研究。为了在细菌中启动转录，催化能力强的核心酶必须与？因子形成全酶。除了？转录起始的因子，经过多年的深入研究，越来越多的证据表明？因子可以参与起始下游的事件，此外，调节因子可以在延伸期间靶向RNAP全酶。对噬菌体的Q抗菌素蛋白进行了验证。它与RNAP全酶在？-依赖的早期伸长暂停。本研究的第一个目的是研究Q在早期伸长期间与RNAP全酶的相互作用，以了解Q获得转录复合物并改变其行为的特殊途径的性质。拟议研究的第二个目的是调查一个？/核心相互作用以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延伸暂停。提出的研究的第三个目的是调查一个意想不到的作用？因子作为转录抗终止剂又是如何存在的？成熟的延伸配合物可能受到调控。总之，目标2和目标3中提出的实验将使我们更深入地了解？转录周期中的因子。

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.