Dynamic nucleoplasmic and nucleolar localization of mammalian RNase H1 in response to RNAP I transcriptional R-loops.

ABSTRACT: An R-loop is a DNA:RNA hybrid formed during transcription when a DNA duplex is invaded by a nascent RNA transcript. R-loops accumulate in nucleoli during RNA polymerase I (RNAP I) transcription. Here, we report that mammalian RNase H1 enriches in nucleoli and co-localizes with R-loops in cultured human cells. Co-migration of RNase H1 and R-loops from nucleoli to perinucleolar ring structures was observed upon inhibition of RNAP I transcription. Treatment with camptothecin which transiently stabilized nucleolar R-loops recruited RNase H1 to the nucleoli. It has been reported that the absence of Topoisomerase and RNase H activity in Escherichia coli or Saccharomyces cerevisiae caused R-loop accumulation along rDNA. We found that the distribution of RNase H1 and Top1 along rDNA coincided at s

SUBMITTER: Shen W 

PROVIDER: S-EPMC5737507 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature