A method for the cell-cycle-specific analysis of radiation-induced chromosome aberrations and breaks

Publication date: Available online 6 April 2019Source: Mutation Research/Fundamental and Molecular Mechanisms of MutagenesisAuthor(s): Aashish Soni, Tamara Murmann-Konda, George IliakisAbstractThe classical G2-assay is widely used to assess cell-radiosensitivity and cancer phenotype: Cells are exposed to low doses of ionizing-radiation (IR) and collected for cytogenetic- analysis ˜1.5 h later. In this way, chromosome-damage is measured in cells irradiated in G2-phase, without retrieving information regarding kinetics of chromosome-break-repair. Modification of the assay to include analysis at multiple time-points after IR, has enabled kinetic-analysis of chromatid-break-repair and assessment of damage in a larger proportion of G2-phase cells. This modification, however, increases the probability that at later time points not only cells irradiated in G2-phase, but also cells irradiated in S-phase will reach metaphase. However, the response of cells irradiated in G2–phase can be mechanistically different from that of cells irradiated in S-phase. Therefore, indiscriminate analysis may confound the interpretation of experiments designed to elucidate mechanisms of chromosome-break-repair and the contributions of the different DSB-repair-pathways in this response. Here we report an EdU based modification of the assay that enables S- and G2–phase specific analysis of chromatid break repair. Our results show that the majority of metaphases captured during the first 2 h after...
Source: Mutation Research Fundamental and Molecular Mechanisms of Mutagenesis - Category: Cytology Source Type: research