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Updated: Oct 10, 2026

Application of Laser Micro-irradiation for Examination of Single and Double Strand Break Repair in Mammalian Cells
Published on: September 5, 2017
Enhanced sensitivity and long-term G2 arrest in hydrogen peroxide-treated Ku80-null cells are unrelated to DNA repair
E D Arrington1, M C Caldwell, T S Kumaravel
1Laboratory of Biological Chemistry, National Institute on Aging, NIH, Baltimore, MD 21224, USA.
Abstract:
While the Ku complex, comprised of Ku70 and Ku80, is primarily involved in the repair of DNA double-strand breaks, it is also believed to participate in additional cellular processes. Here, treatment of embryo fibroblasts (MEFs) derived from either wild-type or Ku80-null (Ku80(-/-)) mice with various stress agents revealed that hydrogen peroxide (H(2)O(2)) was markedly more cytotoxic for Ku80(-/-) MEFs and led to their long-term accumulation in the G2 phase. This differential response was not due to differences in DNA repair, since H(2)O(2)-triggered DNA damage was repaired with comparable efficiency in both Wt and Ku80(-/-) MEFs, but was associated with differences in the expression of important cell cycle regulatory genes. Our results support the notion that Ku80-mediated cytoprotection and G2-progression are not only dependent on the cell's DNA repair but also may reflect Ku80's influence on additional cellular processes such as gene expression.
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