A meiosis-specific protein kinase, Ime2, is required for the correct timing of DNA replication and for spore formation in yeast meiosis

Mol Gen Genet. 1996 Dec 13;253(3):278-88. doi: 10.1007/s004380050323.

Abstract

In this report we study the regulation of premeiotic DNA synthesis in Saccharomyces cerevisiae. DNA replication was monitored by fluorescence-activated cell sorting analysis and by analyzing the pattern of expression of the DNA polymerase alpha-primase complex. Wild-type cells and cells lacking one of the two principal regulators of meiosis, Ime1 and Ime2, were compared. We show that premeiotic DNA synthesis does not occur in ime1 delta diploids, but does occur in ime2 delta diploids with an 8-9 h delay. At late meiotic times, ime2 delta diploids exhibit an additional round of DNA synthesis. Furthermore, we show that in wild-type cells the B-subunit of DNA polymerase alpha is phosphorylated during premeiotic DNA synthesis, a phenomenon that has previously been reported for the mitotic cell cycle. Moreover, the catalytic subunit and the B-subunit of DNA polymerase alpha are specifically degraded during spore formation. Phosphorylation of the B-subunit does not occur in ime1 delta diploids, but does occur in ime2 delta diploids with an 8-9 h delay. In addition, we show that Ime2 is not absolutely required for commitment to meiotic recombination, spindle formation and nuclear division, although it is required for spore formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins*
  • Cell Nucleus / physiology
  • DNA Primase
  • DNA Replication / physiology*
  • DNA, Fungal / biosynthesis
  • Diploidy
  • Flow Cytometry
  • Fluorescent Antibody Technique, Indirect
  • Fungal Proteins / genetics
  • Fungal Proteins / physiology*
  • Intracellular Signaling Peptides and Proteins
  • Meiosis / physiology*
  • Phosphorylation
  • Protein Kinases / genetics
  • Protein Kinases / physiology*
  • Protein-Serine-Threonine Kinases
  • RNA Nucleotidyltransferases / metabolism
  • Recombination, Genetic
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / physiology*
  • Saccharomyces cerevisiae Proteins*
  • Spindle Apparatus / physiology
  • Spores, Fungal / physiology
  • Time Factors

Substances

  • Cell Cycle Proteins
  • DNA, Fungal
  • Fungal Proteins
  • Intracellular Signaling Peptides and Proteins
  • Saccharomyces cerevisiae Proteins
  • Protein Kinases
  • IME2 protein, S cerevisiae
  • Protein-Serine-Threonine Kinases
  • DNA Primase
  • RNA Nucleotidyltransferases