Replication-induced DNA secondary structures drive fork uncoupling and breakage.

Autor: Williams SL; Genome Replication Lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, London, UK., Casas-Delucchi CS; Genome Replication Lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, London, UK., Raguseo F; Chemistry Department, Imperial College London, MSRH, London, UK.; Institute of Chemical Biology, MSRH, London, UK., Guneri D; UCL, School of Pharmacy, London, UK., Li Y; Cavendish Laboratory, University of Cambridge, Cambridge, UK., Minamino M; Francis Crick Institute, London, UK., Fletcher EE; MRC Laboratory of Molecular Biology, Cambridge, UK., Yeeles JT; MRC Laboratory of Molecular Biology, Cambridge, UK., Keyser UF; Cavendish Laboratory, University of Cambridge, Cambridge, UK., Waller ZA; UCL, School of Pharmacy, London, UK., Di Antonio M; Chemistry Department, Imperial College London, MSRH, London, UK.; Institute of Chemical Biology, MSRH, London, UK.; Francis Crick Institute, London, UK., Coster G; Genome Replication Lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, London, UK.
Jazyk: angličtina
Zdroj: The EMBO journal [EMBO J] 2023 Nov 15; Vol. 42 (22), pp. e114334. Date of Electronic Publication: 2023 Oct 02.
DOI: 10.15252/embj.2023114334
Abstrakt: Sequences that form DNA secondary structures, such as G-quadruplexes (G4s) and intercalated-Motifs (iMs), are abundant in the human genome and play various physiological roles. However, they can also interfere with replication and threaten genome stability. Multiple lines of evidence suggest G4s inhibit replication, but the underlying mechanism remains unclear. Moreover, evidence of how iMs affect the replisome is lacking. Here, we reconstitute replication of physiologically derived structure-forming sequences to find that a single G4 or iM arrest DNA replication. Direct single-molecule structure detection within solid-state nanopores reveals structures form as a consequence of replication. Combined genetic and biophysical characterisation establishes that structure stability and probability of structure formation are key determinants of replisome arrest. Mechanistically, replication arrest is caused by impaired synthesis, resulting in helicase-polymerase uncoupling. Significantly, iMs also induce breakage of nascent DNA. Finally, stalled forks are only rescued by a specialised helicase, Pif1, but not Rrm3, Sgs1, Chl1 or Hrq1. Altogether, we provide a mechanism for quadruplex structure formation and resolution during replication and highlight G4s and iMs as endogenous sources of replication stress.
(© 2023 The Authors. Published under the terms of the CC BY 4.0 license.)
Databáze: MEDLINE
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