Abstract
Fanconi anemia (FA) is an inherited cancer predisposition syndrome characterized by cellular hypersensitivity to DNA interstrand crosslinks (ICLs). To repair these lesions, the FA proteins act in a linear hierarchy: following ICL detection on chromatin, the FA core complex monoubiquitinates and recruits the central FANCI and FANCD2 proteins that subsequently coordinate ICL removal and repair of the ensuing DNA double-stranded break by homology-dependent repair (HDR). FANCD2 also functions during the replication stress response by mediating the restart of temporarily stalled replication forks thereby suppressing the firing of new replication origins. To address if FANCI is also involved in these FANCD2-dependent mechanisms, we generated isogenic FANCI-, FANCD2- and FANCI:FANCD2 double-null cells. We show that FANCI and FANCD2 are partially independent regarding their protein stability, nuclear localization and chromatin recruitment and contribute independently to cellular proliferation. Simultaneously, FANCD2––but not FANCI––plays a major role in HDR-mediated replication restart and in suppressing new origin firing. Consistent with this observation, deficiencies in HDR-mediated DNA DSB repair can be overcome by stabilizing RAD51 filament formation in cells lacking functional FANCD2. We propose that FANCI and FANCD2 have partially non-overlapping and possibly even opposing roles during the replication stress response.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 11837-11857 |
| Number of pages | 21 |
| Journal | Nucleic acids research |
| Volume | 45 |
| Issue number | 20 |
| DOIs | |
| State | Published - Nov 16 2017 |
Bibliographical note
Funding Information:National Institutes of Health (NIH) [GM088351, in part, CA194871]; National Cancer Institute [CA190492]; University of Minnesota’s NCI-designated Cancer Center Brainstorm Award (in part); American Cancer Society [RSG-13–039-01-DMC, in part]; DFG [SPP 1230]; Deutsche Jose Carreras Leukämie Stiftung e. V. (to H.H.) (in part); Forschungskommission of the Medical Faculty; Strategische Forschungsverbund (to C.W.); Korean Institute for Basic Science [IBS-R022-A1–2017]. Funding for open access charge: NIH Grant [CA194871]. Conflict of interest statement. E.A.H. declares that he is a member of the scientific advisory boards of Horizon Discovery, Ltd. and Intellia Therapeutics, companies that specialize in applying gene editing technology to basic research and therapeutics. The other authors declare no conflict of interest.
Funding Information:
National Institutes of Health (NIH) [GM088351, in part, CA194871]; National Cancer Institute [CA190492]; University of Minnesota’s NCI-designated Cancer Center Brainstorm Award (in part); American Cancer Society [RSG-13–039-01-DMC, in part]; DFG [SPP 1230]; Deutsche Jose Carreras Leukämie Stiftung e. V. (to H.H.) (in part); Forschungskommission of the Medical Faculty; Strategische Forschungsverbund (to C.W.); Korean Institute for Basic Science [IBS-R022-A1–2017]. Funding for open access charge: NIH Grant [CA194871].
Funding Information:
The authors would like to thank the FA patients and their families for their interest in our research over the years. We are especially grateful to the Fanconi Anemia Research Fund (FARF), Inc. and the German family organizations ‘Fanconi-Anämie-Stiftung e. V.’, ‘Aktionskreis Fanconi-Anämie e.V.’ and ‘Deutsche Fanconi-Anämie-Hilfe e.V.’ for their support of our ideas and work. We would like to thank Dr Sarah Riman for technical help in generating the FANCD2-null cell line and Jihyeon Yang for technical help with cell culture and western blots. We would also like to thank Dr Anja-Katrin Bielinsky for her comments on the manuscript during its preparation. Author Contributions: E.L.T., J.E.Y., O.D.S., E.A.H. and A.S. designed the study and wrote the manuscript. E.L.T., J.E.Y., E.A.L and Y.K. performed experiments. H.H. and C.W. generated and provided novel reagents.
Publisher Copyright:
© The Author(s) 2017.
