title: H2AX phosphorylation in response to DNA double-strand break formation during bystander signalling: effect of microRNA knockdown.
abstract: Upon DNA double-strand break (DSB) formation, hundreds of H2AX molecules in the chromatin flanking the break site are phosphorylated on serine residue 139, termed gamma-H2AX, so that virtually every DSB site in a nucleus can be visualised within 10 min of its formation using an antibody to gamma-H2AX. One application of this sensitive assay is to examine the induction of DNA double-strand damage in subtle non-targeted cellular effects such as the bystander effect. Here whether microRNA (miRNA) serve as a primary signalling mechanism for bystander effect propagation by comparing matched human colon carcinoma cell lines with wild-type or depleted levels of mature miRNAs was investigated. No major differences were found in the levels of induced gamma-H2AX foci in the tested cell lines, indicating that though miRNAs play a role in bystander effect manifestation, they appear not to be the primary bystander signalling molecules in the formation of bystander effect-induced DSBs.
authors.affiliation: Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Dickey
authors.forename: Franz J
authors.initials: FJ
authors.lastname: Zemp
authors.forename: Alvin
authors.initials: A
authors.lastname: Altamirano
authors.forename: Olga A
authors.initials: OA
authors.lastname: Sedelnikova
authors.forename: William M
authors.initials: WM
authors.lastname: Bonner
authors.forename: Olga
authors.initials: O
authors.lastname: Kovalchuk
mesh_terms: D024201:Bystander Effect / Q000235:genetics* / Q000528:radiation effects*; D003110:Colonic Neoplasms / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics*; D004307:Dose-Response Relationship, Radiation; D055785:Gene Knockdown Techniques; D006657:Histones / Q000235:genetics*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D010766:Phosphorylation / Q000528:radiation effects; D011829:Radiation Dosage; D014407:Tumor Cells, Cultured
chemical_list: C468783:H2AX protein, human; D006657:Histones; D035683:MicroRNAs