BRCA1 is required for maintenance of phospho-Chk1 and G2/M arrest during DNA cross-link repair in DT40 cells

Margarethe Draga, Elizabeth B. Madgett, Cassandra J. Vandenberg, David du Plessis, Aisling Kaufmann, Petra Werler, Prasun Chakraborty, Noel F. Lowndes, Kevin Hiom (Lead / Corresponding author)

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    14 Citations (Scopus)
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    The Fanconi anemia DNA repair pathway is pivotal for the efficient repair of DNA interstrand cross-links. Here, we show that FA-defective (Fancc(-)) DT40 cells arrest in G2 phase following cross-link damage and trigger apoptosis. Strikingly, cell death was reduced in Fancc(-) cells by additional deletion of the BRCA1 tumor suppressor, resulting in elevated clonogenic survival. Increased resistance to cross-link damage was not due to loss of toxic BRCA1-mediated homologous recombination but rather through the loss of a G2 checkpoint. This proapoptotic role also required the BRCA1-A complex member ABRAXAS (FAM175A). Finally, we show that BRCA1 promotes G2 arrest and cell death by prolonging phosphorylation of Chk1 on serine 345 after DNA damage to sustain arrest. Our data imply that DNA-induced cross-link death in cells defective in the FA pathway is dependent on the ability of BRCA1 to prolong cell cycle arrest in G2 phase.

    Original languageEnglish
    Pages (from-to)3829-3840
    Number of pages12
    JournalMolecular and Cellular Biology
    Issue number22
    Early online date31 Aug 2015
    Publication statusPublished - Nov 2015


    • Animals
    • Apoptosis
    • Avian proteins
    • BRCA1 protein
    • Carrier proteins
    • Cell line
    • Chickens
    • DNA repair
    • Fanconi anemia
    • Fanconi anemia complementation group C protein
    • G2 phase cell cycle checkpoints
    • Gene deletion
    • Phosphorylation
    • Protein kinases


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