title: RNase H and postreplication repair protect cells from ribonucleotides incorporated in DNA.
abstract: The chemical identity and integrity of the genome is challenged by the incorporation of ribonucleoside triphosphates (rNTPs) in place of deoxyribonucleoside triphosphates (dNTPs) during replication. Misincorporation is limited by the selectivity of DNA replicases. We show that accumulation of ribonucleoside monophosphates (rNMPs) in the genome causes replication stress and has toxic consequences, particularly in the absence of RNase H1 and RNase H2, which remove rNMPs. We demonstrate that postreplication repair (PRR) pathways-MMS2-dependent template switch and Pol ζ-dependent bypass-are crucial for tolerating the presence of rNMPs in the chromosomes; indeed, we show that Pol ζ efficiently replicates over 1-4 rNMPs. Moreover, cells lacking RNase H accumulate mono- and polyubiquitylated PCNA and have a constitutively activated PRR. Our findings describe a crucial function for RNase H1, RNase H2, template switch, and translesion DNA synthesis in overcoming rNTPs misincorporated during DNA replication, and may be relevant for the pathogenesis of Aicardi-Goutières syndrome.
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, 20133 Milano, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Lazzaro
authors.forename: Daniele
authors.initials: D
authors.lastname: Novarina
authors.forename: Flavio
authors.initials: F
authors.lastname: Amara
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Watt
authors.forename: Jana E
authors.initials: JE
authors.lastname: Stone
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Costanzo
authors.forename: Peter M
authors.initials: PM
authors.lastname: Burgers
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kunkel
authors.forename: Paolo
authors.initials: P
authors.lastname: Plevani
authors.forename: Marco
authors.initials: M
authors.lastname: Muzi-Falconi
mesh_terms: D004247:DNA / Q000737:chemistry*; D004260:DNA Repair; D004261:DNA Replication; D042822:Genomic Instability; D018809:Proliferating Cell Nuclear Antigen; D016914:Ribonuclease H / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D013312:Stress, Physiological; D054875:Ubiquitination
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; D016914:Ribonuclease H