Dynein participates in chromosome segregation in fission yeast.
BACKGROUND
In eukaryotic cells, proper formation of the spindle is necessary for successful cell division. For faithful segregation of sister chromatids, each sister kinetochore must attach to microtubules that extend to opposite poles (chromosome bi-orientation). At the metaphase-anaphase transition, cohesion between sister chromatids is removed, and each sister chromatid is pulled to opposite poles of the cell by microtubule-dependent forces.


RESULTS
We have studied the role of the minus-end-directed motor protein dynein by analysing kinetochore dynamics in fission yeast cells deleted for the dynein heavy chain (Dhc1) or the light chain (Dlc1). In these mutants, we found an increased frequency of cells showing defects in chromosome segregation, which leads to the appearance of lagging chromosomes and an increased rate of chromosome loss. By following simultaneously kinetochore dynamics and localization of the checkpoint protein Mad2, we provide evidence that dynein function is not necessary for spindle-assembly checkpoint inactivation. Instead, we have demonstrated that loss of dynein function alters chromosome segregation and activates the Mad2-dependent spindle-assembly checkpoint.


CONCLUSIONS
These results show an unexpected role for dynein in the control of chromosome segregation in fission yeast, most probably operating during the process of bi-orientation during early mitosis.
Courtheoux
Thibault
T
LBCMCP-CNRS UMR5088, Institut d'Exploration, Fonctionelle des Génomes (IFR109), Université Paul, Sabatier, 118 route de Narbonne, 31062 Toulouse, France.
Gay
Guillaume
G
Reyes
Céline
C
Goldstone
Sherilyn
S
Gachet
Yannick
Y
Tournier
Sylvie
S
D000705:Anaphase / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002842:Chromatids / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation / Q000502:physiology*; D015825:Chromosomes, Fungal / Q000235:genetics / Q000378:metabolism*; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018386:Kinetochores / Q000378:metabolism; D064246:Mad2 Proteins; D008677:Metaphase / Q000502:physiology; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism
D018797:Cell Cycle Proteins; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; C577696:mad2 protein, S pombe; C505433:Dhc1 protein, S pombe; C505434:Dlc1 protein, S pombe; D004398:Dyneins