title: 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 replication stress, RPA is a sensor of R loops and a regulator of RNaseH1, extending the versatile role of RPA in suppression of genomic instability.
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Hai Dang
authors.initials: HD
authors.lastname: Nguyen
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Tribhuwan
authors.initials: T
authors.lastname: Yadav
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Sumanprava
authors.initials: S
authors.lastname: Giri
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Borja
authors.initials: B
authors.lastname: Saez
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Graubert
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. Electronic address: zou.lee@mgh.harvard.edu.
authors.forename: Lee
authors.initials: L
authors.lastname: Zou
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D042822:Genomic Instability; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D051716:Replication Protein A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016914:Ribonuclease H / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: C497167:RPA1 protein, human; D051716:Replication Protein A; D012313:RNA; D004247:DNA; D016914:Ribonuclease H; C078856:ribonuclease HI
keywords: R loop; RNase H1; RPA; genome instability; splicing inhibitor; splicing mutation; ssDNA