PT  - JOURNAL ARTICLE
AU  - Timothy T. Harden
AU  - Karina S. Herlambang
AU  - Mathew Chamberlain
AU  - Jean-Benoît Lalanne
AU  - Christopher D. Wells
AU  - Gene-Wei Li
AU  - Robert Landick
AU  - Ann Hochschild
AU  - Jane Kondev
AU  - Jeff Gelles
TI  - Alternative transcription cycle for bacterial RNA polymerase
AID  - 10.1101/663534
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 663534
4099  - http://biorxiv.org/content/early/2019/06/11/663534.short
4100  - http://biorxiv.org/content/early/2019/06/11/663534.full
AB  - 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. We used single-molecule fluorescence microscopy to observe individual RNAP molecules after transcript release at a terminator. Following termination, RNAP almost always remained bound to DNA and sometimes exhibited one-dimensional sliding over thousands of basepairs. Unexpectedly, the DNA-bound RNAP often restarted 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.