title: Sequence-specific double strand breaks trigger P-TEFb-dependent Rpb1-CTD hyperphosphorylation.
abstract: Double strand DNA breaks (DSBs) are one of the most challenging forms of DNA damage which, if left unrepaired, can trigger cellular death and can contribute to cancer. A number of studies have been focused on DNA-damage response (DDR) mechanisms, and most of them rely on the induction of DSBs triggered by chemical compounds or radiations. However, genotoxic drugs and radiation treatments of cultured cell lines induce random DSBs throughout the genome, thus heterogeneously across the cell population, leading to variability of the cellular response. To overcome this aspect, we used here a recently described cell-based DSBs system whereby, upon induction of an inducible restriction enzyme, hundreds of site-specific DSBs are generated across the genome. We show here that sequence-specific DSBs are sufficient to activate the positive transcription elongation factor b (P-TEFb), to trigger hyperphosphorylation of the largest RNA polymerase II carboxyl-terminal-domain (Rpb1-CTD) and to induce activation of p53-transcriptional axis resulting in cell cycle arrest.
authors.affiliation: Department of Biology, University of Naples 'Federico II', Naples, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Napolitano
authors.forename: Stefano
authors.initials: S
authors.lastname: Amente
authors.forename: Miriam Lubrano
authors.initials: ML
authors.lastname: Lavadera
authors.forename: Giacomo
authors.initials: G
authors.lastname: Di Palo
authors.forename: Susanna
authors.initials: S
authors.lastname: Ambrosio
authors.forename: Luigi
authors.initials: L
authors.lastname: Lania
authors.forename: Gaetano Ivan
authors.initials: GI
authors.lastname: Dellino
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Pelicci
authors.forename: Barbara
authors.initials: B
authors.lastname: Majello
mesh_terms: D045744:Cell Line, Tumor; D053903:DNA Breaks, Double-Stranded; D004262:DNA Restriction Enzymes / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation / Q000235:genetics; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: D021122:Protein Subunits; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D042925:Positive Transcriptional Elongation Factor B; D012319:RNA Polymerase II; D004262:DNA Restriction Enzymes
keywords: AsiSI restriction enzyme; P-TEFb; Rpb1-CTD; Site-specific DSBs