title: R loops are linked to histone H3 S10 phosphorylation and chromatin condensation.
abstract: R loops are transcription byproducts that constitute a threat to genome integrity. Here we show that R loops are tightly linked to histone H3 S10 phosphorylation (H3S10P), a mark of chromatin condensation. Chromatin immunoprecipitation (ChIP)-on-chip (ChIP-chip) analyses reveal H3S10P accumulation at centromeres, pericentromeric chromatin, and a large number of active open reading frames (ORFs) in R-loop-accumulating yeast cells, better observed in G1. Histone H3S10 plays a key role in maintaining genome stability, as scored by ectopic recombination and plasmid loss, Rad52 foci, and Rad53 checkpoint activation. H3S10P coincides with the presence of DNA-RNA hybrids, is suppressed by ribonuclease H overexpression, and causes reduced accessibility of restriction endonucleases, implying a tight connection between R loops, H3S10P, and chromatin compaction. Such histone modifications were also observed in R-loop-accumulating Caenorhabditis elegans and HeLa cells. We therefore provide a role of RNA in chromatin structure essential to understand how R loops modulate genome dynamics.
authors.affiliation: Department of Molecular Biology, Universidad de Sevilla-CSIC, Avenida Américo Vespucio, 41092 Seville, Spain.
authors.forename: Maikel
authors.initials: M
authors.lastname: Castellano-Pozo
authors.forename: José M
authors.initials: JM
authors.lastname: Santos-Pereira
authors.forename: Ana G
authors.initials: AG
authors.lastname: Rondón
authors.forename: Sonia
authors.initials: S
authors.lastname: Barroso
authors.forename: Eloisa
authors.initials: E
authors.lastname: Andújar
authors.forename: Mónica
authors.initials: M
authors.lastname: Pérez-Alegre
authors.forename: Tatiana
authors.initials: T
authors.lastname: García-Muse
authors.forename: Andrés
authors.initials: A
authors.lastname: Aguilera
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D047369:Chromatin Immunoprecipitation; D004277:DNA, Single-Stranded / Q000235:genetics*; D042822:Genomic Instability; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008540:Meiosis; D008938:Mitosis; D016366:Open Reading Frames; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012319:RNA Polymerase II / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D029742:Caenorhabditis elegans Proteins; D004277:DNA, Single-Stranded; D006657:Histones; D029701:Saccharomyces cerevisiae Proteins; D012319:RNA Polymerase II