Laser microsurgery provides evidence for merotelic kinetochore attachments in fission yeast cells lacking Pcs1 or Clr4

Cell Cycle. 2010 Oct 1;9(19):3997-4004. doi: 10.4161/cc.9.19.13233. Epub 2010 Oct 3.


In order to segregate chromosomes properly, the cell must prevent merotelic kinetochore attachment, an error that occurs when a single kinetochore is attached to microtubules emanating from both spindle poles. Merotelic kinetochore orientation represents a major mechanism of aneuploidy in mitotic mammalian cells and it is the primary mechanism of chromosome instability in cancer cells. Fission yeast mutants defective in putative microtubule-site clamp Pcs1/Mde4 or Clr4/Swi6-dependent centromeric heterochromatin display high frequencies of lagging chromosomes during anaphase. Here, we developed an assay based on laser microsurgery to show that the stretched morphology of lagging kinetochores in pcs1Δ and clr4Δ mutant cells is due to merotelic attachment. We further show that Mde4 is regulated by Cdc2 and that Cdc2 activity prevents precocious localization of Mde4 to the metaphase spindle. Finally, we show that Pcs1/Mde4 complex shares similar features with the conserved kinetochore complex Spc24/Spc25 suggesting that these two complexes may occupy a similar functional niche.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • CDC2 Protein Kinase / genetics
  • CDC2 Protein Kinase / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Histone-Lysine N-Methyltransferase
  • Kinetochores / metabolism*
  • Kinetochores / ultrastructure
  • Lasers*
  • Methyltransferases / genetics
  • Methyltransferases / metabolism*
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Schizosaccharomyces / cytology*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Sequence Alignment
  • Spindle Apparatus / metabolism*
  • Telomere / metabolism*


  • Cell Cycle Proteins
  • Mde4 protein, S pombe
  • Nuclear Proteins
  • Pcs1 protein, S pombe
  • Recombinant Fusion Proteins
  • Schizosaccharomyces pombe Proteins
  • nuf2 protein, S pombe
  • Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • clr4 protein, S pombe
  • CDC2 Protein Kinase
  • cdc2 protein, S pombe