Skoltech scientists Dmitry Sutormin, Alina Galivondzhyan, Olga Musharova, Dmitrii Travin and Konstantin Severinov published a paper “Interaction between transcribing RNA polymerase and topoisomerase I prevents R-loop formation in E. coli” in Nature Communications. Using ChIP-Seq, the researchers showed that topoisomerase I of Escherichia coli (EcTopoI) is colocalized, genome-wide, with transcribing RNA polymerase (RNAP). Pull-down experiments directly show that the two enzymes interact in vivo. The authors of the paper demonstrated that EcTopoI is enriched upstream of highly-active transcription units, indicating that EcTopoI relaxes negative supercoiling generated by transcription. Moreover, uncoupling of the RNAP:EcTopoI interaction leaded to R-loops accumulation genome-wide, indicating that this interaction is required for prevention of R-loops formation. Full text of the article is available here.