Pathways of DNA double-strand break repair during the mammalian cell cycle.
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TLDR
It is shown here that NHEJ-defective hamster cells (CHO mutant V3 cells) have strongly reduced repair in all cell cycle phases after 1 Gy of irradiation, and HR is particularly important in late S/G2, where both pathways contribute to repair and radioresistance.Abstract:
Little is known about the quantitative contributions of nonhomologous end joining (NHEJ) and homologous recombination (HR) to DNA double-strand break (DSB) repair in different cell cycle phases after physiologically relevant doses of ionizing radiation. Using immunofluorescence detection of -H2AX nuclear foci as a novel approach for monitoring the repair of DSBs, we show here that NHEJ-defective hamster cells (CHO mutant V3 cells) have strongly reduced repair in all cell cycle phases after 1 Gy of irradiation. In contrast, HR-defective CHO irs1SF cells have a minor repair defect in G1, greater impairment in S, and a substantial defect in late S/G2. Furthermore, the radiosensitivity of irs1SF cells is slight in G1 but dramatically higher in late S/G2, while V3 cells show high sensitivity throughout the cell cycle. These findings show that NHEJ is important in all cell cycle phases, while HR is particularly important in late S/G2, where both pathways contribute to repair and radioresistance. In contrast to DSBs produced by ionizing radiation, DSBs produced by the replication inhibitor aphidicolin are repaired entirely by HR. irs1SF, but not V3, cells show hypersensitivity to aphidicolin treatment. These data provide the first evaluation of the cell cycle-specific contributions of NHEJ and HR to the repair of radiation-induced versus replication-associated DSBs.read more
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Sibling rivalry: competition between pol X family members in V(D)J recombination and general double strand break repair
TL;DR: The nonhomologous end‐joining pathway is a major means for repairing double‐strand breaks (DSBs) in all mitotic cell types and suggests surprising complexity in the control of how these different polymerases are employed in this pathway.
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Behind the wheel and under the hood: Functions of cyclin-dependent kinases in response to DNA damage
Lara Wohlbold,Robert P. Fisher +1 more
TL;DR: An overview of data that implicate CDKs in the regulation of DNA damage responses in yeast and metazoans is provided and how the two different, and in some cases opposing, roles ofCDKs could be balanced to produce a coordinated and effective response to DNA damage is considered.
Journal ArticleDOI
Interplay between Cernunnos-XLF and Nonhomologous End-joining Proteins at DNA Ends in the Cell
Peï-Yu Wu,Philippe Frit,Laurent Malivert,Laurent Malivert,Patrick Revy,Patrick Revy,Denis Biard,Bernard Salles,Patrick Calsou +8 more
TL;DR: It is reported that Cernunnos-XLF is corecruited with the core NHEJ components on chromatin damaged with DSBs in human cells and is phosphorylated by the DNA-dependent protein kinase catalytic subunit.
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Roles of Kruppel-associated Box (KRAB)-associated Co-repressor KAP1 Ser-473 Phosphorylation in DNA Damage Response
Chen Hu,Shengping Zhang,Xuan Gao,Xiaojing Gao,Xiaohong Xu,Ya Lv,Yan Zhang,Zhenhong Zhu,Changqing Zhang,Qiao Li,Jiemin Wong,Yongping Cui,Wen Zhang,Lin Ma,Chuangui Wang +14 more
TL;DR: It is shown that, depending on the type of DNA damage that occurs, KAP1 Ser-473 can be phosphorylated by ATM-Chk2 or ATR- Chk1 kinases, which is required for efficient DNA repair and cell survival under stress.
Journal ArticleDOI
Single-Strand Annealing, Conservative Homologous Recombination, Nonhomologous DNA End Joining, and the Cell Cycle-Dependent Repair of DNA Double-Strand Breaks Induced by Sparsely or Densely Ionizing Radiation
TL;DR: It is demonstrated for the first time that in G1-phase SSA is negligible for the repair of DSBs of various complexities, and a defect in SSA confers radiosensitivity to cells in S phase, suggesting that the error-prone SSA mechanism is important for the Repair of specific simple and complex DSBS that are not a substrate for HR or NHEJ.
References
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DNA Double-stranded Breaks Induce Histone H2AX Phosphorylation on Serine 139
TL;DR: In this paper, a histone H2AX species that has been phosphorylated specifically at serine 139 was found to be a major component of DNA double-stranded break.
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Megabase chromatin domains involved in DNA double-strand breaks in vivo.
TL;DR: The results offer direct visual confirmation that γ-H2AX forms en masse at chromosomal sites of DNA double-strand breaks and suggest the possible existence of units of higher order chromatin structure involved in monitoring DNA integrity.
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Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses
Kai Rothkamm,Markus Löbrich +1 more
TL;DR: Evidence is presented that foci of γ-H2AX (a phosphorylated histone), detected by immunofluorescence, are quantitatively the same as DSBs and are capable of quantifying the repair of individual D SBs, allowing the investigation of DSB repair after radiation doses as low as 1 mGy, an improvement by several orders of magnitude over current methods.
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