Bending the rules of transcriptional repression: tightly looped DNA directly represses T7 RNA polymerase.

ABSTRACT: From supercoiled DNA to the tight loops of DNA formed by some gene repressors, DNA in cells is often highly bent. Despite evidence that transcription by RNA polymerase (RNAP) is affected in systems where DNA is deformed significantly, the mechanistic details underlying the relationship between polymerase function and mechanically stressed DNA remain unclear. Seeking to gain additional insight into the regulatory consequences of highly bent DNA, we hypothesize that tightly looping DNA is alone sufficient to repress transcription. To test this hypothesis, we have developed an assay to quantify transcription elongation by bacteriophage T7 RNAP on small, circular DNA templates approximately 100 bp in size. From these highly bent transcription templates, we observe that the elongation velocity

SUBMITTER: Lionberger TA 

PROVIDER: S-EPMC2920717 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature