R-ChIP for genome-wide mapping of R-loops by using catalytically inactive RNASEH1

Nat Protoc. 2019 May;14(5):1661-1685. doi: 10.1038/s41596-019-0154-6. Epub 2019 Apr 17.

Abstract

Nascent RNA may form a three-stranded structure with DNA, called an R-loop, which has been linked to fundamental biological processes such as transcription, replication and genome instability. Here, we provide a detailed protocol for a newly developed strategy, named R-ChIP, for robust capture of R-loops genome-wide. Distinct from R-loop-mapping methods based on the monoclonal antibody S9.6, which recognizes RNA-DNA hybrid structures, R-ChIP involves expression of an exogenous catalytically inactive RNASEH1 in cells to bind RNA-DNA hybrids but not resolve them. This is followed by chromatin immunoprecipitation (ChIP) of the tagged RNASEH1 and construction of a strand-specific library for deep sequencing. It takes ~3 weeks to establish a stable cell line expressing the mutant enzyme and 5 more days to proceed with the R-ChIP protocol. In principle, R-ChIP is applicable to both cell lines and animals, as long as the catalytically inactive RNASEH1 can be expressed to study the dynamics of R-loop formation and resolution, as well as its impact on the functionality of the genome. In our recent studies with R-ChIP, we showed an intimate spatiotemporal relationship between R-loops and RNA polymerase II pausing/pause release, as well as linking augmented R-loop formation to DNA damage response induced by driver mutations of key splicing factors associated with myelodysplastic syndrome (MDS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chromatin Immunoprecipitation / methods*
  • Chromosome Mapping / methods*
  • DNA / chemistry
  • DNA / genetics
  • RNA / chemistry
  • RNA / genetics*
  • Ribonuclease H / chemistry
  • Ribonuclease H / genetics*
  • Ribonuclease H / metabolism

Substances

  • RNA
  • DNA
  • Ribonuclease H
  • ribonuclease HI