Low dose ionizing radiation strongly stimulates insertional mutagenesis in a γH2AX dependent manner

English version

Autoři: Alex N. Zelensky ^aff001; Mascha Schoonakker ^aff001; Inger Brandsma ^aff001; Marcel Tijsterman ^aff003; Dik C. van Gent ^aff001; Jeroen Essers ^aff001; Roland Kanaar ^aff001
Působiště autorů: Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands ^aff001; Oncode Institute, Erasmus University Medical Center, Rotterdam, The Netherlands ^aff002; Human Genetics, Leiden University Medical Center, Leiden, The Netherlands ^aff003; Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands ^aff004; Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands ^aff005
Vyšlo v časopise: Low dose ionizing radiation strongly stimulates insertional mutagenesis in a γH2AX dependent manner. PLoS Genet 16(1): e32767. doi:10.1371/journal.pgen.1008550
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pgen.1008550

Souhrn

Extrachromosomal DNA can integrate into the genome with no sequence specificity producing an insertional mutation. This process, which is referred to as random integration (RI), requires a double stranded break (DSB) in the genome. Inducing DSBs by various means, including ionizing radiation, increases the frequency of integration. Here we report that non-lethal physiologically relevant doses of ionizing radiation (10–100 mGy), within the range produced by medical imaging equipment, stimulate RI of transfected and viral episomal DNA in human and mouse cells with an extremely high efficiency. Genetic analysis of the stimulated RI (S-RI) revealed that it is distinct from the background RI, requires histone H2AX S139 phosphorylation (γH2AX) and is not reduced by DNA polymerase θ (Polq) inactivation. S-RI efficiency was unaffected by the main DSB repair pathway (homologous recombination and non-homologous end joining) disruptions, but double deficiency in MDC1 and 53BP1 phenocopies γH2AX inactivation. The robust responsiveness of S-RI to physiological amounts of DSBs can be exploited for extremely sensitive, macroscopic and direct detection of DSB-induced mutations, and warrants further exploration in vivo to determine if the phenomenon has implications for radiation risk assessment.

Klíčová slova:

DNA – DNA damage – Electroporation – Gene targeting – HeLa cells – Non-homologous end joining – Transfection – Ionizing radiation

Zdroje

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