Functions of Replication Protein A as a Sensor of R Loops and a Regulator of RNaseH1.

ABSTRACT: R loop, a transcription intermediate containing RNA:DNA hybrids and displaced single-stranded DNA (ssDNA), has emerged as a major source of genomic instability. RNaseH1, which cleaves the RNA in RNA:DNA hybrids, plays an important role in R loop suppression. Here we show that replication protein A (RPA), an ssDNA-binding protein, interacts with RNaseH1 and colocalizes with both RNaseH1 and R loops in cells. In vitro, purified RPA directly enhances the association of RNaseH1 with RNA:DNA hybrids and stimulates the activity of RNaseH1 on R loops. An RPA binding-defective RNaseH1 mutant is not efficiently stimulated by RPA in vitro, fails to accumulate at R loops in cells, and loses the ability to suppress R loops and associated genomic instability. Thus, in addition to sensing DNA damage and

SUBMITTER: Nguyen HD 

PROVIDER: S-EPMC5507214 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature