Mfd translocase is necessary and sufficient for transcription-coupled repair in Escherichia coli [Computational Biology]

Nucleotide excision repair in E. coli is stimulated by transcription, specifically in the transcribed strand (TS). Previously, it was shown that this transcription-coupled repair (TCR) is mediated by the Mfd translocase. Recently, it was proposed that in fact the majority of TCR in E. coli is catalyzed by a second pathway ('backtracking-mediated TCR') that is dependent on the UvrD helicase and the ppGpp alarmone/stringent response regulator. Recently, we reported that as measured by the Excision Repair-Sequencing XR-seq), UvrD plays no role in TCR genome-wide. Here, we tested the role of ppGpp and UvrD in TCR genome-wide and in the lacZ operon using the XR-seq method which directly measures repair. We find that the mfd mutation abolishes TCR genome-wide and in the lacZ operon. In contrast, the relA-spoT-mutant deficient in ppGpp synthesis carries out normal TCR. We conclude that UvrD and ppGpp play no role in TCR in E. coli.

from # All Medicine by Alexandros G. Sfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2gip9or
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