title: Transcription inhibition by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) causes DNA damage and triggers homologous recombination repair in mammalian cells.
abstract: Transcription, replication and homologous recombination are intrinsically connected and it is well established that an increase of transcription is associated with an increase in homologous recombination. Here, we have studied how homologous recombination is affected during transcription inhibition by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), a compound that prevents activating phosphorylations of the RNA Pol II C-terminal domain. We identify that DRB triggers an increase in homologous recombination within the hprt gene as well as increasing RAD51 foci formation in mammalian cells. Furthermore, we find that DRB-induced transcriptional stress is associated with formation of the nuclear foci of the phosphorylated form of H2AX (γH2AX). We accounted that about 72% of RAD51 foci co-localized with the observed γH2AX foci. Interestingly, we find that XRCC3 mutated, homologous recombination defective cells are hypersensitive to the toxic effect of DRB and fail to form RAD51 foci. In conclusion, we show that DRB-induced transcription inhibition is associated with the formation of a lesion that triggers RAD51-dependent homologous recombination repair, required for survival under transcriptional stress.
authors.affiliation: Department of Genetics Microbiology and Toxicology, Stockholm University, Stockholm, Sweden.
authors.forename: Ivaylo
authors.initials: I
authors.lastname: Stoimenov
authors.forename: Ponnari
authors.initials: P
authors.lastname: Gottipati
authors.forename: Niklas
authors.initials: N
authors.lastname: Schultz
authors.forename: Thomas
authors.initials: T
authors.lastname: Helleday
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D018613:Microscopy, Confocal; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D006657:Histones; C110901:X-ray repair cross complementing protein 3; D004004:Dichlororibofuranosylbenzimidazole; D007041:Hypoxanthine Phosphoribosyltransferase; D051135:Rad51 Recombinase