PMID:22099310
| Citation |
Zhou, J, Ha, KS, La Porta, A, Landick, R and Block, SM (2011) Applied force provides insight into transcriptional pausing and its modulation by transcription factor NusA. Mol. Cell 44:635-46 |
|---|---|
| Abstract |
Transcriptional pausing by RNA polymerase (RNAP) plays an essential role in gene regulation. Pausing is modified by various elongation factors, including prokaryotic NusA, but the mechanisms underlying pausing and NusA function remain unclear. Alternative models for pausing invoke blockade events that precede translocation (on-pathway), enzyme backtracking (off-pathway), or isomerization to a nonbacktracked, elemental pause state (off-pathway). We employed an optical trapping assay to probe the motions of individual RNAP molecules transcribing a DNA template carrying tandem repeats encoding the his pause, subjecting these enzymes to controlled forces. NusA significantly decreased the pause-free elongation rate of RNAP while increasing the probability of entry into short- and long-lifetime pauses, in a manner equivalent to exerting a ~19 pN force opposing transcription. The effects of force and NusA on pause probabilities and lifetimes support a reaction scheme where nonbacktracked, elemental pauses branch off the elongation pathway from the pretranslocated state of RNAP. |
| Links |
PubMed PMC3227225 Online version:10.1016/j.molcel.2011.09.018 |
| Keywords |
DNA, Bacterial/chemistry; DNA, Bacterial/genetics; DNA-Directed RNA Polymerases/genetics; DNA-Directed RNA Polymerases/metabolism; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Gene Expression Regulation, Bacterial; Kinetics; Optical Processes; Optical Tweezers; Peptide Elongation Factors/genetics; Peptide Elongation Factors/metabolism; Plasmids; Tandem Repeat Sequences; Templates, Genetic; Transcription Factors/genetics; Transcription Factors/metabolism; Transcription, Genetic |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
See also
References
See Help:References for how to manage references in EcoliWiki.