Unrestrained 53BP1 activity at DNA double-strand breaks (DSBs) hampers DNA end resection and upsets DSB repair pathway choice. RNF169 acts as a molecular rheostat to limit 53BP1 deposition at DSBs, but how this fine balance translates to DSB repair control remains undefined. In striking contrast to 53BP1, ChIP analyses of ASI-induced DSBs unveiled that RNF169 exhibits robust accumulation at DNA end-proximal regions and preferentially targets resected, RPA-bound DSBs. Accordingly, we found that RNF169 promotes CtIP-dependent DSB resection and favors homology-mediated DSB repair, and further showed that RNF169 dose-dependently stimulates single-strand annealing repair, in part, by alleviating the 53BP1-imposed barrier to DSB end resection. Our results highlight the interplay of RNF169 with 53BP1 in fine-tuning choice of DSB repair pathways.
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http://dx.doi.org/10.1073/pnas.1804823115 | DOI Listing |
Radiat Res
December 2024
Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany.
It is thought that cells surviving ionizing radiation exposure repair DNA double-strand breaks (DSBs) and restore their genomes. However, the recent biochemical and genetic characterization of DSB repair pathways reveals that only homologous recombination (HR) can function in an error-free manner and that the non-homologous end joining (NHEJ) pathways canonical NHEJ (c-NHEJ), alternative end joining (alt-EJ), and single-strand annealing (SSA) are error-prone, and potentially leave behind genomic scars and altered genomes. The strong cell cycle restriction of HR to S/G2 phases and the unparalleled efficiency of c-NHEJ throughout the cell cycle, raise the intriguing question as to how far a surviving cell "reaches" after repairing the genome back to its pre-irradiation state.
View Article and Find Full Text PDFCurr Opin Pharmacol
December 2024
Biotechnology Research and Innovation Council - National Institute of Immunology (BRIC-NII), Aruna Asaf Ali Marg, New Delhi 110067, India; Biotechnology Research and Innovation Council - National Institute of Biomedical Genomics (BRIC-NIBMG), Kalyani 741251, India. Electronic address:
DNA damage signaling is a highly coordinated cellular process which is required for the removal of DNA lesions. Amongst the different types of DNA damage, double-strand breaks (DSBs) are the most harmful type of lesion that attenuates cellular proliferation. DSBs are repaired by two major pathways-homologous recombination (HR), and non-homologous end-joining (NHEJ) and in some cases by microhomology-mediated end-joining (MMEJ).
View Article and Find Full Text PDFiScience
December 2024
Division of Molecular Oncological Pharmacy, Faculty of Pharmacy, Keio University, 1-5-30, Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
DNA double-strand breaks (DSBs) occurring within the genomic DNA of mammalian cells significantly impact cell survival, depending upon their repair capacity. This study presents a mathematical model to fit fibroblast survival rates with a sequence-specific DSB burden induced by the restriction enzyme AsiSI. When cells had a sporadic DSB burden under mixed culture, cell growth showed a good fit to the Lotka-Volterra competitive equation, predicting the presence of modifying factors acting as competitive cell-to-cell interactions compared to monocultures.
View Article and Find Full Text PDFThe Mre11 complex comprises Mre11, Rad50 and Nbs1 (Xrs2 in ). The core components, Mre11 and Rad50 are highly conserved, with readily identifiable orthologs in all clades of life, whereas Nbs1/Xrs2 are present only in eukaryotes. In eukaryotes, the complex is integral to the DNA damage response, acting in DNA double strand break (DSB) detection and repair, and the activation of DNA damage signaling.
View Article and Find Full Text PDFMol Biol (Mosk)
December 2024
Institute of Functional Genomics, Moscow State University, Moscow, 119991 Russia.
The CRISPR/Cas technology of targeted genome editing made it possible to carry out genetic engineering manipulations with eukaryotic genomes with a high efficiency. Targeted induction of site-specific DNA breaks is one of the key stages of the technology. The cell repairs the breaks via one of the two pathways, nonhomologous end joining (NHEJ) and homology-driven repair (HDR).
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