title: The repair of G-quadruplex-induced DNA damage.
abstract: G4 DNA motifs, which can form stable secondary structures called G-quadruplexes, are ubiquitous in eukaryotic genomes, and have been shown to cause genomic instability. Specialized helicases that unwind G-quadruplexes in vitro have been identified, and they have been shown to prevent genetic instability in vivo. In the absence of these helicases, G-quadruplexes can persist and cause replication fork stalling and collapse. Translesion synthesis (TLS) and homologous recombination (HR) have been proposed to play a role in the repair of this damage, but recently it was found in the nematode Caenorhabditis elegans that G4-induced genome alterations are generated by an error-prone repair mechanism that is dependent on the A-family polymerase Theta (Pol θ). Current data point towards a scenario where DNA replication blocked at G-quadruplexes causes DNA double strand breaks (DSBs), and where the choice of repair pathway that can act on these breaks dictates the nature of genomic alterations that are observed in various organisms.
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
authors.forename: Maartje
authors.initials: M
authors.lastname: van Kregten
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands. Electronic address: m.tijsterman@lumc.nl.
authors.forename: Marcel
authors.initials: M
authors.lastname: Tijsterman
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics*; D004261:DNA Replication; D054856:G-Quadruplexes; D042822:Genomic Instability
keywords: DNA repair; DNA replication; G-quadruplexes; Genomic instability