6533b85bfe1ef96bd12bb65b

RESEARCH PRODUCT

Compromised repair of radiation-induced DNA double-strand breaks in Fanconi anemia fibroblasts in G2

Gundula RöschDetlev SchindlerHeinz SchmidbergerSebastian ZahnreichBritta Weber

subject

DNA End-Joining RepairBiologyBiochemistryFanconi Anemia Complementation Group F ProteinHistonesRecombinases03 medical and health scienceschemistry.chemical_compound0302 clinical medicineFanconi anemiaChromosome instabilitymedicineHumansDNA Breaks Double-StrandedFanconi Anemia Complementation Group G ProteinMolecular BiologyCells Cultured030304 developmental biologyBRCA2 ProteinChromosome Aberrations0303 health sciencesFanconi Anemia Complementation Group A ProteinFanconi Anemia Complementation Group D2 ProteinX-RaysCell CycleFanconi Anemia Complementation Group C ProteinRecombinational DNA RepairChromosomeDNACell BiologyFibroblastsCell cyclemedicine.diseaseFanconi Anemia Complementation Group E ProteinComplementationKineticsenzymes and coenzymes (carbohydrates)Fanconi Anemiachemistry030220 oncology & carcinogenesisPremature chromosome condensationMutationCancer researchChromatidTumor Suppressor p53-Binding Protein 1DNA

description

Fanconi anemia (FA) is a rare chromosomal instability syndrome with various clinical features and high cancer incidence. Despite being a DNA repair disorder syndrome and a frequently observed clinical hypersensitivity of FA patients towards ionizing radiation, the experimental evidence regarding the efficiency of radiation-induced DNA double-strand break (DSB) repair in FA is very controversial. Here, we performed a thorough analysis of the repair of radiation-induced DSBs in G1 and G2 in FA fibroblasts of complementation groups A, C, D1 (BRCA2), D2, E, F, G and P (SLX4) in comparison to normal human lung and skin fibroblasts. γH2AX, 53BP1, or RPA foci quantification after X-irradiation was combined with cell cycle markers. Cytogenetic analyses were performed on first metaphases after irradiation in G1 and by premature chromosome condensation after exposure in G2. Furthermore, the role of canonical-NHEJ and alternative-NHEJ for the fidelity of the repair of radiation-induced DSBs was examined. In FA fibroblasts, DSB repair was normal in G1 but compromised and more error-prone in the slow repair component of G2 as suggested by higher yields of radiation-induced γH2AX and 53BP1 foci as well as chromatid exchanges. However, RPA foci quantification in G2 indicated proficiency for homology-directed repair of DSBs in FA except for FA D1 (BRCA2). In lung fibroblasts, DSB repair in G1 was conducted with normal kinetics but elevated chromosome exchanges compared to skin fibroblasts. The overall repair of radiation-induced DSBs and the formation of chromosome exchanges in normal and FA fibroblasts in G1 and G2 were governed by canonical-NHEJ with no contribution of alternative-NHEJ. Together, we show impaired repair of radiation-induced DSBs in various FA complementation groups in the slow repair component of G2 that might promote the formation of potentially oncogenic aberrations and clinical radiation hypersensitivity.

yearjournalcountryeditionlanguage
2020-06-15DNA Repair
https://doi.org/10.1016/j.dnarep.2020.102992