Mek1 coordinates meiotic progression with DNA break repair by directly phosphorylating and inhibiting the yeast pachytene exit regulator Ndt80

PLoS Genet. 2018 Nov 29;14(11):e1007832. doi: 10.1371/journal.pgen.1007832. eCollection 2018 Nov.

Abstract

Meiotic recombination plays a critical role in sexual reproduction by creating crossovers between homologous chromosomes. These crossovers, along with sister chromatid cohesion, connect homologs to enable proper segregation at Meiosis I. Recombination is initiated by programmed double strand breaks (DSBs) at particular regions of the genome. The meiotic recombination checkpoint uses meiosis-specific modifications to the DSB-induced DNA damage response to provide time to convert these breaks into interhomolog crossovers by delaying entry into Meiosis I until the DSBs have been repaired. The meiosis-specific kinase, Mek1, is a key regulator of meiotic recombination pathway choice, as well as being required for the meiotic recombination checkpoint. The major target of this checkpoint is the meiosis-specific transcription factor, Ndt80, which is essential to express genes necessary for completion of recombination and meiotic progression. The molecular mechanism by which cells monitor meiotic DSB repair to allow entry into Meiosis I with unbroken chromosomes was unknown. Using genetic and biochemical approaches, this work demonstrates that in the presence of DSBs, activated Mek1 binds to Ndt80 and phosphorylates the transcription factor, thus inhibiting DNA binding and preventing Ndt80's function as a transcriptional activator. Repair of DSBs by recombination reduces Mek1 activity, resulting in removal of the inhibitory Mek1 phosphates. Phosphorylation of Ndt80 by the meiosis-specific kinase, Ime2, then results in fully activated Ndt80. Ndt80 upregulates transcription of its own gene, as well as target genes, resulting in prophase exit and progression through meiosis.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Cell Cycle Checkpoints
  • Conserved Sequence
  • DNA Breaks, Double-Stranded
  • DNA Repair*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Genes, Fungal
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • MAP Kinase Kinase 1 / genetics
  • MAP Kinase Kinase 1 / metabolism*
  • Meiosis / genetics
  • Meiosis / physiology*
  • Models, Biological
  • Models, Molecular
  • Mutation
  • Pachytene Stage / genetics
  • Pachytene Stage / physiology
  • Phosphorylation
  • Protein Interaction Domains and Motifs
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Proteolysis
  • Recombinational DNA Repair
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Sequence Homology, Amino Acid
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • DNA-Binding Proteins
  • Intracellular Signaling Peptides and Proteins
  • NDT80 protein, S cerevisiae
  • RED1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • IME2 protein, S cerevisiae
  • Protein Serine-Threonine Kinases
  • MAP Kinase Kinase 1