The Structure-Specific Endonuclease Ercc1-Xpf Is Required To Resolve DNA Interstrand Cross-Link-Induced Double-Strand Breaks

• DOI: 10.1128/mcb.24.13.5776-5787.2004
• Publication Date: 2004-06-16T03:28:14Z
• Authors: Laura J. Niedernh...; Hanny Odijk; Magda Budzowska; Ellen van Drunen; Alex Maas; Arjan F. Theil; Jan de Wit; N. G. J. Jaspers; H. Berna Beverloo; Jan H. J. Hoeijma...; Roland Kanaar
• Keywords: ERCC1

AbstractInterstrand cross-links (ICLs) are an extremely toxic class of DNA damage incurred during normal metabolism or cancer chemotherapy. ICLs covalently tether both strands duplex DNA, preventing the strand unwinding that is essential for polymerase access. The mechanism ICL repair in mammalian cells poorly understood. However, genetic data implicate Ercc1-Xpf endonuclease and proteins required homologous recombination-mediated double-strand break (DSB) repair. To examine role repair, we monitored phosphorylation histone variant H2AX (γ-H2AX). phosphoprotein accumulates at DSBs, forming foci can be detected by immunostaining. Treatment wild-type with mitomycin C (MMC) induced γ-H2AX increased amount DSBs pulsed-field gel electrophoresis. Surprisingly, were also Ercc1−/− MMC treatment. Thus, occur after cross-link via Ercc1-independent mechanism. Instead, ICL-induced DSB formation cell cycle progression into S phase, suggesting intermediate form replication. In cells, MMC-induced persisted least 48 h longer than demonstrating Ercc1 resolution cross-link-induced DSBs. triggered sister chromatid exchanges but fusions Xpf mutant indicating their absence, prevented. Collectively, these support a processing so cytotoxic intermediates repaired recombination. This study was supported grants from European Union, Dutch Cancer Society (K.W.F.), Netherlands Organization Scientific Research (NWO). L.J.N. postdoctoral fellowship PF-99-142 American Society.