Role of PCNA and TLS polymerases in D-loop extension during homologous recombination in humans

• Published in: DNA repair Vol. 12; no. 9; pp. 691 - 698
• Main Authors: Sebesta, Marek, Burkovics, Peter, Juhasz, Szilvia, Zhang, Sufang, Szabo, Judit E., Lee, Marietta Y.W.T., Haracska, Lajos, Krejci, Lumir
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-09-2013; Elsevier
• Subjects: D-loop; DNA Damage; DNA Polymerase III - chemistry; DNA Polymerase III - physiology; DNA repair synthesis; DNA Replication; DNA, Single-Stranded - biosynthesis; DNA-Directed DNA Polymerase - chemistry; DNA-Directed DNA Polymerase - physiology; HeLa Cells; Homologous Recombination; Humans; Osmolar Concentration; Proliferating Cell Nuclear Antigen - chemistry; Proliferating Cell Nuclear Antigen - physiology; Rad51 Recombinase - chemistry; Reconstitution; RNA-Binding Protein FUS - chemistry; RNA-Binding Protein FUS - physiology; TLS polymerases; Reconstitution; D-loop; DNA repair synthesis; Homologous recombination; TLS polymerases
• ISSN: 1568-7864; 1568-7856
• DOI: 10.1016/j.dnarep.2013.05.001

Homologous recombination (HR) is essential for maintaining genomic integrity, which is challenged by a wide variety of potentially lethal DNA lesions. Regardless of the damage type, recombination is known to proceed by RAD51-mediated D-loop formation, followed by DNA repair synthesis. Nevertheless, the participating polymerases and extension mechanism are not well characterized. Here, we present a reconstitution of this step using purified human proteins. In addition to Pol δ, TLS polymerases, including Pol η and Pol κ, also can extend D-loops. In vivo characterization reveals that Pol η and Pol κ are involved in redundant pathways for HR. In addition, the presence of PCNA on the D-loop regulates the length of the extension tracks by recruiting various polymerases and might present a regulatory point for the various recombination outcomes.