RNF4 and PLK1 are required for replication fork collapse in ATR-deficient cells

Ryan L. Ragland, Sima Patel, Rebecca S. Rivard, Kevin Smith, Ashley A. Peters, Anja K Bielinsky, Eric J. Brown

Research output: Contribution to journalArticlepeer-review

86 Scopus citations


The ATR-CHK1 axis stabilizes stalled replication forks and prevents their collapse into DNA double-strand breaks (DSBs). Here, we show that fork collapse in Atr-deleted cells is mediated through the combined effects the sumo targeted E3-ubiquitin ligase RNF4 and activation of the AURKA-PLK1 pathway. As indicated previously, Atrdeleted cells exhibited a decreased ability to restart DNA replication following fork stalling in comparison with control cells. However, suppression of RNF4, AURKA, or PLK1 returned the reinitiation of replication in Atrdeleted cells to near wild-type levels. In RNF4-depleted cells, this rescue directly correlated with the persistence of sumoylation of chromatin-bound factors. Notably, RNF4 repression substantially suppressed the accumulation of DSBs in ATR-deficient cells, and this decrease in breaks was enhanced by concomitant inhibition of PLK1. DSBs resulting from ATR inhibition were also observed to be dependent on the endonuclease scaffold protein SLX4, suggesting that RNF4 and PLK1 either help activate the SLX4 complex or make DNA replication fork structures accessible for subsequent SLX4-dependent cleavage. Thus, replication fork collapse following ATR inhibition is a multistep process that disrupts replisome function and permits cleavage of the replication fork.

Original languageEnglish (US)
Pages (from-to)2259-2273
Number of pages15
JournalGenes and Development
Issue number20
StatePublished - Oct 15 2013


  • ATR
  • PLK1
  • RNF4
  • Replication fork collapse
  • SLX4
  • SUMO


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