CUL-2 LRR-1 and UBXN-3 drive replisome disassembly during DNA replication termination and mitosis

Nat Cell Biol. 2017 May;19(5):468-479. doi: 10.1038/ncb3500. Epub 2017 Apr 3.

Abstract

Replisome disassembly is the final step of DNA replication in eukaryotes, involving the ubiquitylation and CDC48-dependent dissolution of the CMG helicase (CDC45-MCM-GINS). Using Caenorhabditis elegans early embryos and Xenopus laevis egg extracts, we show that the E3 ligase CUL-2LRR-1 associates with the replisome and drives ubiquitylation and disassembly of CMG, together with the CDC-48 cofactors UFD-1 and NPL-4. Removal of CMG from chromatin in frog egg extracts requires CUL2 neddylation, and our data identify chromatin recruitment of CUL2LRR1 as a key regulated step during DNA replication termination. Interestingly, however, CMG persists on chromatin until prophase in worms that lack CUL-2LRR-1, but is then removed by a mitotic pathway that requires the CDC-48 cofactor UBXN-3, orthologous to the human tumour suppressor FAF1. Partial inactivation of lrr-1 and ubxn-3 leads to synthetic lethality, suggesting future approaches by which a deeper understanding of CMG disassembly in metazoa could be exploited therapeutically.

Publication types

  • Video-Audio Media

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / enzymology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Chromatin / enzymology*
  • Chromatin / genetics
  • Chromatin Assembly and Disassembly
  • Cullin Proteins / genetics
  • Cullin Proteins / metabolism*
  • DNA / biosynthesis*
  • DNA / genetics
  • Genotype
  • Mitosis*
  • Multiprotein Complexes
  • Oocytes
  • Phenotype
  • RNA Interference
  • S Phase*
  • Time Factors
  • Ubiquitination
  • Valosin Containing Protein
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism
  • Xenopus laevis / genetics
  • Xenopus laevis / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • Cell Cycle Proteins
  • Chromatin
  • Cullin Proteins
  • Multiprotein Complexes
  • UBXN-3 protein, C elegans
  • Xenopus Proteins
  • cul-2 proteins, C elegans
  • DNA
  • Adenosine Triphosphatases
  • Valosin Containing Protein