Fission yeast dam1-A8 mutant is resistant to and rescued by an anti-microtubule agent.
The Dam1/DASH outer kinetochore complex is required for high-fidelity chromosome segregation in budding and fission yeast. Unlike budding yeast, the fission yeast complex is non-essential, however it promotes bipolar microtubule attachment in conjunction with microtubule-depolymerising kinesin-8 Klp5 and Klp6. Here, we screened for dam1 temperature sensitive mutants in a klp5 null background and identified dam1-A8 that contains two amino acid substitutions in the C-terminus (H126R and E149G). dam1-A8klp5 mutant cells display massive chromosome missegregation with lagging chromosomes and monopolar attachment of sister chromatids to one SPB (spindle pole body). Unexpectedly contrary to a deletion mutant that is hypersensitive to microtubule-destabilising drugs, dam1-A8 is resistant and furthermore the temperature sensitivity of dam1-A8klp5 is rescued by addition of these drugs. This indicates that the hyper-stabilised rigidity of kinetochore-spindle mal-attachments is the primary cause of lethality. Our result shows that fine-tuning of Dam1 activity is essential for chromosome bi-orientation.
Griffiths
Karen
K
Laboratory of Cell Regulation, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
Masuda
Hirohisa
H
Dhut
Susheela
S
Toda
Takashi
T
D018797:Cell Cycle Proteins / Q000235:genetics*; D020090:Chromosome Segregation / Q000187:drug effects / Q000235:genetics*; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008870:Microtubules / Q000187:drug effects* / Q000235:genetics*; D009154:Mutation; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D012568:Schizosaccharomyces / Q000187:drug effects* / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics*
D018797:Cell Cycle Proteins; C116003:DAM1 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins