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Transcription elongation is responsible for rapid synthesis of RNA chains of thousands of nucleotides in vivo. In contrast, a single round of transcription performed in vitro is frequently interrupted by pauses and arrests that drastically reduce the elongation rate and the yield of the full-length transcript. Here we demonstrate that most transcriptional(More)
RNA chain elongation is a highly processive and accurate process that is finely regulated by numerous intrinsic and extrinsic signals. Here we describe a general mechanism that governs RNA polymerase (RNAP) movement and response to regulatory inputs such as pauses, terminators, and elongation factors. We show that E.coli RNAP moves by a complex Brownian(More)
Rho is the essential RNA helicase that sets the borders between transcription units and adjusts transcriptional yield to translational needs in bacteria. Although Rho was the first termination factor to be discovered, the actual mechanism by which it reaches and disrupts the elongation complex (EC) is unknown. Here we show that the termination-committed Rho(More)
Frequent codirectional collisions between the replisome and RNA polymerase (RNAP) are inevitable because the rate of replication is much faster than that of transcription. Here we show that, in E. coli, the outcome of such collisions depends on the productive state of transcription elongation complexes (ECs). Codirectional collisions with backtracked(More)
UvrD helicase is required for nucleotide excision repair, although its role in this process is not well defined. Here we show that Escherichia coli UvrD binds RNA polymerase during transcription elongation and, using its helicase/translocase activity, forces RNA polymerase to slide backward along DNA. By inducing backtracking, UvrD exposes DNA lesions(More)
The small molecule alarmone (p)ppGpp mediates bacterial adaptation to nutrient deprivation by altering the initiation properties of RNA polymerase (RNAP). ppGpp is generated in Escherichia coli by two related enzymes, RelA and SpoT. We show that ppGpp is robustly, but transiently, induced in response to DNA damage and is required for efficient nucleotide(More)
Bacterial small RNAs (sRNAs) have been implicated in various aspects of post-transcriptional gene regulation. Here, we demonstrate that sRNAs also act at the level of transcription termination. We use the rpoS gene, which encodes a general stress sigma factor σ(S), as a model system, and show that sRNAs DsrA, ArcZ, and RprA bind the rpoS 5'UTR to suppress(More)
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