Srs2 promotes synthesis-dependent strand annealing by disrupting DNA polymerase d-extending D-loops

Jie Liu, Christopher Ede, William D. Wright, Steven K. Gore, Shirin S. Jenkins, Bret D. Freudenthal, M. Todd Washington, Xavier Veaute, Wolf Dietrich Heyer

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25 Scopus citations

Abstract

Synthesis-dependent strand annealing (SDSA) is the preferred mode of homologous recombination in somatic cells leading to an obligatory non-crossover outcome, thus avoiding the potential for chromosomal rearrangements and loss of heterozygosity. Genetic analysis identified the Srs2 helicase as a prime candidate to promote SDSA. Here, we demonstrate that Srs2 disrupts D-loops in an ATP-dependent fashion and with a distinct polarity. Specifically, we partly reconstitute the SDSA pathway using Rad51, Rad54, RPA, RFC, DNA Polymerase d with different forms of PCNA. Consistent with genetic data showing the requirement for SUMO and PCNA binding for the SDSA role of Srs2, Srs2 displays a slight but significant preference to disrupt extending D-loops over unextended D-loops when SUMOylated PCNA is present, compared to unmodified PCNA or monoubiquitinated PCNA. Our data establish a biochemical mechanism for the role of Srs2 in crossover suppression by promoting SDSA through disruption of extended D-loops.

Original languageEnglish (US)
Article numbere22195
JournaleLife
Volume6
DOIs
StatePublished - May 23 2017

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Liu, J., Ede, C., Wright, W. D., Gore, S. K., Jenkins, S. S., Freudenthal, B. D., Washington, M. T., Veaute, X., & Heyer, W. D. (2017). Srs2 promotes synthesis-dependent strand annealing by disrupting DNA polymerase d-extending D-loops. eLife, 6, [e22195]. https://doi.org/10.7554/eLife.22195