Pathways of DNA double-strand break repair during the mammalian cell cycle.
Reads0
Chats0
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
Citations
More filters
Journal ArticleDOI
Toward A variable RBE for proton beam therapy.
Henning Willers,Antiño R. Allen,David R. Grosshans,Stephen J. McMahon,Cläre von Neubeck,Claudia Wiese,Bhadrasain Vikram +6 more
TL;DR: Experimental data on the repair of proton damage to DNA that impact both RBE values and biophysical modeling to predict RBE variations are reviewed and recent clinical findings discussed.
Journal ArticleDOI
Suppression of Nonhomologous End Joining Repair by Overexpression of HMGA2
Angela Y J Li,Angela Y J Li,Lee Ming Boo,Shih Ya Wang,H. Helen Lin,Clay C. C. Wang,Yun Yen,Benjamin P C Chen,David J. Chen,David K. Ann,David K. Ann +10 more
TL;DR: A novel role for HMGA2 to interfere with NHEJ processes was uncovered, implicatingHMGA2 in the promotion of genome instability and tumorigenesis.
Journal ArticleDOI
Effective PEI-mediated delivery of CRISPR-Cas9 complex for targeted gene therapy.
Nari Ryu,Min-A Kim,Dongsik Park,Byeonghyeon Lee,Ye-Ri Kim,Kyung-Hee Kim,Jeong-In Baek,Won Jong Kim,Kyu-Yup Lee,Un-Kyung Kim,Un-Kyung Kim +10 more
TL;DR: It is demonstrated that BPEI-25K is a promising non-viral vector to deliver the CRISPR/Cas9 system in vitro to mediate targeted gene therapy, and these findings contribute to an understanding of CRISpr/ Cas9 delivery that may enable development of successful in vivo techniques.
Journal ArticleDOI
Inhibiting homologous recombination for cancer therapy
TL;DR: The rationale for seeking inhibitors of homologous recombination (HR) repair for use in cancer therapy is reviewed, in which blocking two alternative pathways that a cell can use to reach a needed end-point has a much bigger impact than blocking either pathway alone.
Journal ArticleDOI
The shape of the radiation dose response for DNA double-strand break induction and repair
TL;DR: Some of the biological and methodological factors that can potentially modify the shape of the dose response curve obtained using the most common assays for double-strand breaks, pulsed-field gel electrophoresis and microscopic scoring of radiation-induced foci are identified.
References
More filters
Journal ArticleDOI
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.
Journal ArticleDOI
Genome maintenance mechanisms for preventing cancer
TL;DR: This review summarizes the main DNA caretaking systems and their impact on genome stability and carcinogenesis.
Journal ArticleDOI
A specific inhibitor of phosphatidylinositol 3-kinase, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002).
TL;DR: One such compound, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one, LY294002, completely and specifically abolished PtdIns 3-kinase activity, which may be beneficial in the treatment of proliferative diseases as well as in elucidating the biological role of the kinase in cellular proliferation and growth factor response.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Related Papers (5)
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