Interaction of Chk1 with Treslin negatively regulates the initiation of chromosomal DNA replication

Mol Cell. 2015 Feb 5;57(3):492-505. doi: 10.1016/j.molcel.2014.12.003. Epub 2014 Dec 31.


Treslin helps to trigger the initiation of DNA replication by promoting integration of Cdc45 into the replicative helicase. Treslin is a key positive-regulatory target of cell-cycle control mechanisms; activation of Treslin by cyclin-dependent kinase is essential for the initiation of replication. Here we demonstrate that Treslin is also a critical locus for negative regulatory mechanisms that suppress initiation. We found that the checkpoint-regulatory kinase Chk1 associates specifically with a C-terminal domain of Treslin (designated TRCT). Mutations in the TRCT domain abolish binding of Chk1 to Treslin and thereby eliminate Chk1-catalyzed phosphorylation of Treslin. Significantly, abolition of the Treslin-Chk1 interaction results in elevated initiation of chromosomal DNA replication during an unperturbed cell cycle, which reveals a function for Chk1 during a normal S phase. This increase is due to enhanced loading of Cdc45 onto potential replication origins. These studies provide important insights into how vertebrate cells orchestrate proper initiation of replication.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Binding Sites
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Checkpoint Kinase 1
  • Chromosomes / metabolism
  • DNA Replication*
  • HEK293 Cells
  • Humans
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism*
  • Xenopus laevis / embryology
  • Xenopus laevis / genetics
  • Xenopus laevis / metabolism*


  • CDC45 protein, human
  • Cdc45 protein, Xenopus
  • Cell Cycle Proteins
  • TICRR protein, Xenopus
  • TICRR protein, human
  • Xenopus Proteins
  • Protein Kinases
  • CHEK1 protein, human
  • Checkpoint Kinase 1
  • Chek1 protein, Xenopus