Checkpoint controls that couple mitosis to completion of DNA replication

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M Roberge1

  • 1Department of Biochemistry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 123.

Trends in Cell Biology
|September 1, 1992
PubMed

Insights

Cells halt mitosis when DNA replication is incomplete, preventing M-phase kinase activation. This DNA damage checkpoint ensures proper cell cycle progression, preventing errors during cell division.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Cells typically enter mitosis only after DNA replication is complete.
  • Inhibitors of DNA synthesis normally arrest cells before mitosis.
  • A regulatory mechanism prevents mitosis when DNA is incompletely replicated.

Purpose of the Study:

  • To review recent developments in understanding the DNA replication checkpoint.
  • To discuss the mechanism preventing M-phase kinase activation.
  • To explore the role of RCC1-Ran complex in detecting unreplicated DNA.

Main Methods:

  • Review of existing literature on cell cycle regulation.
  • Analysis of molecular mechanisms controlling M-phase kinase activity.
  • Discussion of DNA damage signaling pathways.

Main Results:

  • Incompletely replicated DNA prevents M-phase kinase activation by inhibiting dephosphorylation of a critical tyrosine residue.
  • The control system may also target NIMA protein kinase.
  • RCC1-Ran complex likely detects and signals unreplicated DNA.

Conclusions:

  • A regulatory system prevents mitosis when DNA synthesis is incomplete.
  • This system ensures mitosis strictly follows S phase in the normal cell cycle.
  • Understanding this checkpoint is crucial for cell cycle control and cancer research.

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