Role of DNA bubble rewinding in enzymatic transcription termination.
By using DNA heteroduplexes that inhibit rewinding of the upstream part of the transcription bubble, we show that transcript release in termination by the enzymes Mfd and Rho is facilitated by reannealing of DNA in the upstream region of the transcription bubble, as is also true for termination by intrinsic terminators. We also show that, like Mfd, the Rho termination factor promotes forward translocation of RNA polymerase. These results support termination models in which external forces imposed on nucleic acids induce concerted rewinding of DNA and unwinding of the DNA/RNA hybrid, possibly accompanied by forward translocation of RNA polymerase, leading to transcription complex dissociation.
Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA.
Joo-Seop
JS
Park
Jeffrey W
JW
Roberts
D001426:Bacterial Proteins / Q000378:metabolism; D001692:Biological Transport; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA / Q000235:genetics / Q000378:metabolism; D013728:Terminator Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*
D001426:Bacterial Proteins; D014157:Transcription Factors; C072103:transcription repair coupling factor protein, Bacteria; D012313:RNA; D004247:DNA