title: The yeast and human FACT chromatin-reorganizing complexes solve R-loop-mediated transcription-replication conflicts.
abstract: FACT (facilitates chromatin transcription) is a chromatin-reorganizing complex that swaps nucleosomes around the RNA polymerase during transcription elongation and has a role in replication that is not fully understood yet. Here we show that recombination factors are required for the survival of yeast FACT mutants, consistent with an accumulation of DNA breaks that we detected by Rad52 foci and transcription-dependent hyperrecombination. Breaks also accumulate in FACT-depleted human cells, as shown by γH2AX foci and single-cell electrophoresis. Furthermore, FACT-deficient yeast and human cells show replication impairment, which in yeast we demonstrate by ChIP-chip (chromatin immunoprecipitation [ChIP] coupled with microarray analysis) of Rrm3 to occur genome-wide but preferentially at highly transcribed regions. Strikingly, in yeast FACT mutants, high levels of Rad52 foci are suppressed by RNH1 overexpression; R loops accumulate at high levels, and replication becomes normal when global RNA synthesis is inhibited in FACT-depleted human cells. The results demonstrate a key function of FACT in the resolution of R-loop-mediated transcription-replication conflicts, likely associated with a specific chromatin organization.
authors.affiliation: Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, 41092 Seville, Spain.
authors.forename: Emilia
authors.initials: E
authors.lastname: Herrera-Moyano
authors.forename: Xénia
authors.initials: X
authors.lastname: Mergui
authors.forename: María L
authors.initials: ML
authors.lastname: García-Rubio
authors.forename: Sonia
authors.initials: S
authors.lastname: Barroso
authors.forename: Andrés
authors.initials: A
authors.lastname: Aguilera
mesh_terms: D002470:Cell Survival / Q000235:genetics; D002843:Chromatin / Q000378:metabolism*; D053960:DNA Breaks; D004261:DNA Replication / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D042822:Genomic Instability / Q000235:genetics; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D016914:Ribonuclease H / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology*; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; C541535:FACT protein, S cerevisiae; D006609:High Mobility Group Proteins; C073537:SSRP1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D035602:Transcriptional Elongation Factors; D016914:Ribonuclease H; C078856:ribonuclease HI
keywords: FACT; R loops; chromatin reorganization; genome instability; transcription–replication collisions