Downstream DNA tension regulates the stability of the T7 RNA polymerase initiation complex.

ABSTRACT: Gene transcription by the enzyme RNA polymerase is tightly regulated. In many cases, such as in the lac operon in Escherichia coli, this regulation is achieved through the action of protein factors on DNA. Because DNA is an elastic polymer, its response to enzymatic processing can lead to mechanical perturbations (e.g., linear stretching and supercoiling) that can affect the operation of other DNA processing complexes acting elsewhere on the same substrate molecule. Using an optical-tweezers assay, we measured the binding kinetics between single molecules of bacteriophage T7 RNA polymerase and DNA, as a function of tension. We found that increasing DNA tension under conditions that favor formation of the open complex results in destabilization of the preinitiation complex. Furthermore, wit

SUBMITTER: Skinner GM 

PROVIDER: S-EPMC3037602 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature