title: Stimulation of Chromosomal Rearrangements by Ribonucleotides.
abstract: We show by whole genome sequence analysis that loss of RNase H2 activity increases loss of heterozygosity (LOH) in Saccharomyces cerevisiae diploid strains harboring the pol2-M644G allele encoding a mutant version of DNA polymerase ε that increases ribonucleotide incorporation. This led us to analyze the effects of loss of RNase H2 on LOH and on nonallelic homologous recombination (NAHR) in mutant diploid strains with deletions of genes encoding RNase H2 subunits (rnh201Δ, rnh202Δ, and rnh203Δ), topoisomerase 1 (TOP1Δ), and/or carrying mutant alleles of DNA polymerases ε, α, and δ. We observed an ∼7-fold elevation of the LOH rate in RNase H2 mutants encoding wild-type DNA polymerases. Strains carrying the pol2-M644G allele displayed a 7-fold elevation in the LOH rate, and synergistic 23-fold elevation in combination with rnh201Δ. In comparison, strains carrying the pol2-M644L mutation that decreases ribonucleotide incorporation displayed lower LOH rates. The LOH rate was not elevated in strains carrying the pol1-L868M or pol3-L612M alleles that result in increased incorporation of ribonucleotides during DNA synthesis by polymerases α and δ, respectively. A similar trend was observed in an NAHR assay, albeit with smaller phenotypic differentials. The ribonucleotide-mediated increases in the LOH and NAHR rates were strongly dependent on TOP1. These data add to recent reports on the asymmetric mutagenicity of ribonucleotides caused by topoisomerase 1 processing of ribonucleotides incorporated during DNA replication.
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523 Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: Hailey N
authors.initials: HN
authors.lastname: Conover
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Lujan
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Chapman
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Cornelio
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: Rabab
authors.initials: R
authors.lastname: Sharif
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709.
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Williams
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709.
authors.forename: Alan B
authors.initials: AB
authors.lastname: Clark
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: Francheska
authors.initials: F
authors.lastname: Camilo
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709 lucas.argueso@colostate.edu kunkel@niehs.nih.gov.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kunkel
authors.affiliation: Department of Environmental and Radiological Health Sciences and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado 80523 Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709 lucas.argueso@colostate.edu kunkel@niehs.nih.gov.
authors.forename: Juan Lucas
authors.identifier: http://orcid.org/0000-0002-7157-1519
authors.initials: JL
authors.lastname: Argueso
mesh_terms: D004257:DNA Polymerase II / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism; D004271:DNA, Fungal / Q000096:biosynthesis; D015321:Gene Rearrangement; D005800:Genes, Fungal; D042822:Genomic Instability; D059785:Karyotype; D019656:Loss of Heterozygosity; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014178:Translocation, Genetic
chemical_list: D004271:DNA, Fungal; D012265:Ribonucleotides; D029701:Saccharomyces cerevisiae Proteins; D004257:DNA Polymerase II; D012260:Ribonucleases; C569437:Rnh201 protein, S cerevisiae; D004264:DNA Topoisomerases, Type I
keywords: LOH; NAHR; genome stability; recombination; ribonucleotides