title: Transcription termination factor rho mediates simultaneous release of RNA transcripts and DNA template from complexes with Escherichia coli RNA polymerase.
abstract: Dissociation of RNA and DNA from Escherichia coli RNA polymerase in transcription complexes prepared with enzyme molecules located within and near a rho-dependent transcription termination region on bacteriophage T7 D111 DNA has been studied using a membrane filter-binding assay. Rho protein with ATP present mediated rapid (half-time approximately 27 s) simultaneous dissociation of about 50% of both RNA and DNA. RNA molecules were preferentially released from enzyme molecules located within the termination region. Rapid release of RNA and DNA depended on a nucleoside triphosphate but did not depend on sigma factor. Pretreatment of complexes with ribonuclease prevented dissociation of DNA. Nearly simultaneous dissociation of both RNA and DNA was also detected after a lag of 3 min when the isolated transcription complexes were incubated with all four ribonucleoside triphosphates in the absence of rho factor. In this case, release presumably occurred at the rho-independent termination site that is 5990 nucleotides downstream from the A1 promoter. Thus, the dissociation of DNA from RNA polymerase at rho-dependent and rho-independent transcription termination sites is coupled with or occurs spontaneously soon after the release of transcripts at both sites.
mesh_terms: D004279:DNA, Viral / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D012367:RNA, Viral / Q000378:metabolism*; D012234:Rho Factor / Q000494:pharmacology*; D012808:Sigma Factor / Q000494:pharmacology; D013604:T-Phages / Q000235:genetics; D013698:Templates, Genetic; D014157:Transcription Factors / Q000494:pharmacology*; D014158:Transcription, Genetic
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D012234:Rho Factor; D012808:Sigma Factor; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases