title: The RAD51 paralogs ensure cellular protection against mitotic defects and aneuploidy.
abstract: The interplay between homologous DNA recombination and mitotic progression is poorly understood. The five RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3) are key enzymes for DNA double-strand break repair. In our search for specific functions of the various RAD51 paralogs, we found that inhibition of XRCC3 elicits checkpoint defects, while inhibition of RAD51B or RAD51C induces G2/M cell cycle arrest in HeLa cells. Using live-cell microscopy we show that in XRCC3-knockdown cells the spindle assembly checkpoint persists and there is a higher frequency of chromosome misalignments, anaphase bridges, and aneuploidy. We observed centrosome defects in the absence of XRCC3. While RAD51B and RAD51C act early in homologous recombination, XRCC3 functions jointly with GEN1 later in the pathway at the stage of Holliday junction resolution. Our data demonstrate that Holliday junction resolution has critical functions for preventing aberrant mitosis and aneuploidy in mitotic cells.
authors.affiliation: Genome Stability Laboratory, Laval University Cancer Research Centre, Hôtel-Dieu de Québec Research Centre (CHUQ), 9 McMahon, Québec, QC G1R 2J6, Canada.
authors.forename: Amélie
authors.initials: A
authors.lastname: Rodrigue
authors.forename: Yan
authors.initials: Y
authors.lastname: Coulombe
authors.forename: Karine
authors.initials: K
authors.lastname: Jacquet
authors.forename: Jean-Phillipe
authors.initials: JP
authors.lastname: Gagné
authors.forename: Céline
authors.initials: C
authors.lastname: Roques
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gobeil
authors.forename: Guy
authors.initials: G
authors.lastname: Poirier
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Masson
mesh_terms: D000782:Aneuploidy; D015153:Blotting, Western; D045566:DNA, Cruciform / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D045565:Holliday Junction Resolvases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000235:genetics; D034622:RNA Interference
chemical_list: D045566:DNA, Cruciform; D004268:DNA-Binding Proteins; C413002:RAD51B protein, human; C448305:RAD51C protein, human; C112629:RAD51D protein, human; C110901:X-ray repair cross complementing protein 3; C113187:XRCC2 protein, human; C533748:GEN1 protein, human; D045565:Holliday Junction Resolvases