Radiation-induced XRCC4 Association with Chromatin DNA Analyzed by Biochemical Fractionation

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概要

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• XRCC4, in association with DNA ligase IV, is thought to play a critical role in the ligation of two DNA ends in DNA double-strand break (DSB) repair through non-homologous end-joining (NHEJ) pathway. In the present study, we captured radiation-induced chromatin-recruitment of XRCC4 by biochemical fractionation using detergent Nonidet P-40. A subpopulation of XRCC4 changed into a form that is resistant to the extraction with 0.5% Nonidet P-40-containing buffer after irradiation. This form of XRCC4 was liberated by micrococcal nuclease treatment, indicating that it had been tethered to chromatin DNA. This chromatin-recruitment of XRCC4 could be seen immediately (< 0.1 hr) after irradiation and remained up to 4 hr after 20 Gy irradiation. It was seen even after irradiation of small doses, i.e., 2 Gy, but the residence of XRCC4 on chromatin was very transient after 2 Gy irradiation, returning to near normal level in 0.2–0.5 hr after irradiation. The chromatin-bound XRCC4 represented only ~1% of total XRCC4 molecules even after 20 Gy irradiation and the quantitative analysis using purified protein as the reference suggested that only a few XRCC4-DNA ligase IV complexes were recruited to each DNA end. We further show that the chromatin-recruitment of XRCC4 was not attenuated by wortmannin, an inhibitor of DNA-PK, or siRNA-mediated knockdown of the DNA-PK catalytic subunit (DNA-PKcs), indicating that this process does not require DNA-PKcs. These results would provide us with useful experimental tools and important insights to understand the DNA repair process through NHEJ pathway.

• 2010-05-16

著者

• KAMDAR Radhika

  Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Tokyo Institute of T

• MATSUMOTO Yoshihisa

  Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Tokyo Institute of T

• Kamdar Radhika

  Research Laboratory For Nuclear Reactors And Department Of Nuclear Engineering Tokyo Institute Of Te

• Matsumoto Yoshihisa

  Research Laboratory For Nuclear Reactors And Department Of Nuclear Engineering Tokyo Institute Of Te

関連論文

• Role of DNA Double-strand Break Repair Genes in Cell Proliferation under Low Dose-rate Irradiation Conditions
• Radiation-induced XRCC4 Association with Chromatin DNA Analyzed by Biochemical Fractionation

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