Protein/Protein Interactions in Prokaryotic Gene Control

描述（由申请人提供）：细菌中的转录通过从细菌到人类保守的多亚基RNA聚合酶（RNAP）进行。启动子特异性转录起始依赖于？RNAP是RNAP的一个亚基，它必须与催化活性强的核心酶结合形成全酶。历史上被定义为一个启动因素，？也可以保持与转录延伸复合物结合并在延伸期间影响转录过程。尤其是，？可以通过与基因的初始转录区内的启动子样DNA序列元件建立序列特异性相互作用来诱导早期延伸暂停。拟议的研究建立在这样的启动子样暂停诱导元素可以发挥抑制？在伸长的最早阶段的损失，增加？整个转录单位的延伸复合物的含量。生物信息学分析的结果表明，启动子近端？依赖暂停元素与所有E的至少20%相关联。大肠杆菌启动子，这意味着这种机制的调节？延伸复合物的含量可能是E.杆菌建议的研究的第一个目的是调查的影响？保留在E. coli基因表达。第二个目的是调查是否潜在的作用？在转录过程中延伸超出了初级？因素，并确定是否不同类型的？因子可以参与同一转录单位的起始和延伸（？“交叉监管”）。第三个目的是探讨启动子-近端停顿成分影响启动子-近端停顿的机制。下游延伸复合物的含量。第四个目的是调查是否有一个具体的？核心的相互作用，可能是必不可少的细胞活力促进释放？在一个暂停的早期延伸复合体的背景下从DNA中分离出来。总之，拟议的实验将导致一个经典的起始因子在转录延伸过程中的作用有了更深入的了解，有助于积累的证据，在原核生物和真核生物的启动后监管事件的重要性。

DESCRIPTION (provided by applicant): Transcription in bacteria is carried out by a multi-subunit RNA polymerase (RNAP) that is conserved from bacteria to humans. Promoter-specific transcription initiation depends on the ??subunit of RNAP, which must associate with the catalytically proficient core enzyme to form the holoenzyme. Historically defined as an initiation factor, ? can also remain associated with the transcription elongation complex and influence the transcription process during elongation. In particular, ? can induce early elongation pausing by establishing sequence-specific interactions with promoter-like DNA sequence elements within the initial transcribed region of a gene. The proposed research builds on the demonstration that such promoter-like pause- inducing elements can function to inhibit ? loss during the earliest stage of elongation, increasing the ? content of elongation complexes throughout the transcription unit. The results of bioinformatic analyses suggest that promoter-proximal ?-dependent pause elements are associated with at least 20% of all E. coli promoters, which implies that this mechanism for regulating the ? content of elongation complexes is likely a general feature of transcription in E. coli. The first aim of the proposed research is to investigae the effects of ? retention on E. coli gene expression. The second aim is to investigate whether the potential roles for ? during transcription elongation extend beyond the primary ? factors and to determine whether different types of ? factors can participate in initiation and elongation on the same transcription unit (? "cross-regulation"). The third aim is to investigate the mechanism by which promoter-proximal pause elements influence the ? content of downstream elongation complexes. The fourth aim is to investigate whether a specific ?-core interaction that may be essential for cell viability facilitates the release of ? from the DNA in the context of a paused early elongation complex. Together, the proposed experiments will lead to a deeper understanding of the roles of a classical initiation factor during transcription elongation, contributing to an accumulating body of evidence for the importance of post-initiation regulatory events in both prokaryotes and eukaryotes.