FANCJ promotes DNA synthesis through G-quadruplex structures

Pau Castillo Bosch, Sandra Segura-Bayona, Wouter Koole, Jane T van Heteren, James M Dewar, Marcel Tijsterman, Puck Knipscheer

Research output: Contribution to journal/periodicalArticleScientificpeer-review

Abstract

Our genome contains many G-rich sequences, which have the propensity to fold into stable secondary DNA structures called G4 or G-quadruplex structures. These structures have been implicated in cellular processes such as gene regulation and telomere maintenance. However, G4 sequences are prone to mutations particularly upon replication stress or in the absence of specific helicases. To investigate how G-quadruplex structures are resolved during DNA replication, we developed a model system using ssDNA templates and Xenopus egg extracts that recapitulates eukaryotic G4 replication. Here, we show that G-quadruplex structures form a barrier for DNA replication. Nascent strand synthesis is blocked at one or two nucleotides from the G4. After transient stalling, G-quadruplexes are efficiently unwound and replicated. In contrast, depletion of the FANCJ/BRIP1 helicase causes persistent replication stalling at G-quadruplex structures, demonstrating a vital role for this helicase in resolving these structures. FANCJ performs this function independently of the classical Fanconi anemia pathway. These data provide evidence that the G4 sequence instability in FANCJ(-/-) cells and Fancj/dog1 deficient C. elegans is caused by replication stalling at G-quadruplexes.

Original languageEnglish
Pages (from-to)2521-33
Number of pages13
JournalEMBO Journal
Volume33
Issue number21
DOIs
Publication statusPublished - 03 Nov 2014

Keywords

  • Animals
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins
  • DNA
  • DNA Helicases
  • DNA Replication
  • G-Quadruplexes
  • Gene Deletion
  • Humans
  • Xenopus laevis

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