DNA polymerase alpha, a component of the replication initiation complex, is essential for the checkpoint coupling S phase to mitosis in fission yeast

G. D'Urso, B. Grallert, P. Nurse

Research output: Contribution to journalArticlepeer-review

105 Scopus citations

Abstract

Genetic analysis in the yeast Schizosaccharomyces pombe has shown that three genes cdc18, cut5, and cdt1, are essential for DNA synthesis and also for the checkpoint control that couples completion of DNA replication to the onset of mitosis. To test whether assembly of the replication initiation complex is an important element in the checkpoint control pathway we have investigated if DNA polymerase alpha (pol1), a component of the initiation complex, is essential for the S-phase checkpoint control. We show that germinating S. pombe spores disrupted for the pol1 gene enter mitosis despite defects in DNA synthesis. This is shown by monitoring septation index, DNA content, and by direct immunofluorescence of mitotic spindles using antibodies to alpha-tubulin. In addition we have isolated six temperature sensitive mutants in the pol1 gene that cause cell cycle arrest when grown at the non-permissive temperature. Our experiments support a model in which DNA polymerase alpha, in addition to being part of the initiation complex, is required for a checkpoint signal that is activated as cells traverse START, and is essential to prevent mitosis until S phase has been completed. In contrast, proteins responsible for the elongation of DNA may not be necessary for this checkpoint signal.

Original languageEnglish (US)
Pages (from-to)3109-3118
Number of pages10
JournalJournal of Cell Science
Volume108
Issue number9
StatePublished - Jan 1 1995
Externally publishedYes

Keywords

  • DNA polymerase alpha
  • Mitosis
  • Replication initiation complex
  • S phase
  • Schizosaccharomyces pombe

ASJC Scopus subject areas

  • Cell Biology

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