Alternative transcription cycle for bacterial RNA polymerase

• Published in: Nature communications 2020-01, Vol.11 (1), p.448-448, Article 448
• Main Authors: Harden, Timothy T., Herlambang, Karina S., Chamberlain, Mathew, Lalanne, Jean-Benoît, Wells, Christopher D., Li, Gene-Wei, Landick, Robert, Hochschild, Ann, Kondev, Jane, Gelles, Jeff
• Format: Article
• Language: English
• Subjects: 38/77; 38/91; 631/337/572; 631/57/2265; 64; 82/83; Adenosine Triphosphate - genetics; Antisense RNA; Cytidine Triphosphate - genetics; Deoxyribonucleic acid; DNA; DNA - genetics; DNA - metabolism; DNA, Antisense - genetics; DNA-directed RNA polymerase; DNA-Directed RNA Polymerases - chemistry; DNA-Directed RNA Polymerases - genetics; DNA-Directed RNA Polymerases - metabolism; Elongation; Escherichia coli - enzymology; Escherichia coli - genetics; Fluorescence; Fluorescence microscopy; Gene expression; Gene regulation; Gene sequencing; Genomes; Humanities and Social Sciences; Microscopy, Fluorescence; multidisciplinary; Promoter Regions, Genetic; Ribonucleic acid; RNA; RNA polymerase; Science; Science (multidisciplinary); Single Molecule Imaging; Transcription, Genetic
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-14208-9

RNA polymerases (RNAPs) transcribe genes through a cycle of recruitment to promoter DNA, initiation, elongation, and termination. After termination, RNAP is thought to initiate the next round of transcription by detaching from DNA and rebinding a new promoter. Here we use single-molecule fluorescence microscopy to observe individual RNAP molecules after transcript release at a terminator. Following termination, RNAP almost always remains bound to DNA and sometimes exhibits one-dimensional sliding over thousands of basepairs. Unexpectedly, the DNA-bound RNAP often restarts transcription, usually in reverse direction, thus producing an antisense transcript. Furthermore, we report evidence of this secondary initiation in live cells, using genome-wide RNA sequencing. These findings reveal an alternative transcription cycle that allows RNAP to reinitiate without dissociating from DNA, which is likely to have important implications for gene regulation. In the canonical bacterial transcription, both nascent transcript and polymerase dissociate from template DNA. By employing multi-color single-molecule fluorescence imaging, here the authors show that RNA polymerases remain bound to DNA after the transcript release.