RPA activates the XPF-ERCC1 endonuclease to initiate processing of DNA interstrand crosslinks

Abdullah, Ummi B; McGouran, Joanna F; Brolih, Sanja; Ptchelkine, Denis; El‐Sagheer, Afaf H; Brown, Tom; McHugh, Peter J

Type

Article

Authors

Abdullah, Ummi B
McGouran, Joanna F
Brolih, Sanja
Ptchelkine, Denis
El‐Sagheer, Afaf H
Brown, Tom
McHugh, Peter J

Date

2017-06-13

Permanent link to this record

http://hdl.handle.net/10754/625123

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Abstract

During replication-coupled DNA interstrand crosslink (ICL) repair, the XPF-ERCC1 endonuclease is required for the incisions that release, or “unhook”, ICLs, but the mechanism of ICL unhooking remains largely unknown. Incisions are triggered when the nascent leading strand of a replication fork strikes the ICL. Here, we report that while purified XPF-ERCC1 incises simple ICL-containing model replication fork structures, the presence of a nascent leading strand, modelling the effects of replication arrest, inhibits this activity. Strikingly, the addition of the single-stranded DNA (ssDNA)-binding replication protein A (RPA) selectively restores XPF-ERCC1 endonuclease activity on this structure. The 5′–3′ exonuclease SNM1A can load from the XPF-ERCC1-RPA-induced incisions and digest past the crosslink to quantitatively complete the unhooking reaction. We postulate that these collaborative activities of XPF-ERCC1, RPA and SNM1A might explain how ICL unhooking is achieved in vivo.

Citation

Abdullah UB, McGouran JF, Brolih S, Ptchelkine D, El-Sagheer AH, et al. (2017) RPA activates the XPF-ERCC1 endonuclease to initiate processing of DNA interstrand crosslinks. The EMBO Journal: e201796664. Available: http://dx.doi.org/10.15252/embj.201796664.

Sponsors

We thank our laboratory member Sook Y. Lee and Opher Gileadi (Structural Genomics Consortium, Oxford) for the recombinant SNM1A; Fumiko Esashi (Dunn School of Pathology, University of Oxford) and Marc Wold (Iowa State University, USA) for the RPA and RPA70ΔC442, respectively; Hannah Baddock (WIMM), Hazel Aitkenhead and Joseph A. Newman (Structural Genomics Consortium, University of Oxford) for assistance with fluorescence anisotropy. P.J.M. was supported by MRC (Medical Research Council, grant MR/L007665/1). A.H.E.S. and T.B. were supported by BBSRC (Biotechnology and Biological Sciences Research Council, grant BB/J001694/1) BBSRC: sLOLA grant BB/J001694/1 “Extending the boundaries of nucleic acid chemistry” J.F.M. was supported by King Abdullah University of Science and Technology (KAUST) for a grant awarded to B. Nordén. U.B.A. was supported by the Malaysia's King Scholarship (Biasiswa Yang Di-Pertuan Agong).