Control of Shugoshin function during fission-yeast meiosis.
Meiosis consists of a single round of DNA replication followed by two consecutive nuclear divisions. During the first division (MI), sister kinetochores must orient toward the same pole to favor reductional segregation. Correct chromosome segregation during the second division (MII) requires the retention of centromeric cohesion until anaphase II. The spindle checkpoint protein Bub1 is essential for both processes in fission yeast . When bub1 is deleted, the Shugoshin protein Sgo1 is not recruited to centromeres, cohesin Rec8 does not persist at centromeres, and sister-chromatid cohesion is lost by the end of MI. Deletion of bub1 also affects kinetochore orientation because sister centromeres can move to opposite spindle poles in approximately 30% of MI divisions. We show here that these two functions are separable within the Bub1 protein. The N terminus of Bub1 is necessary and sufficient for Sgo1 targeting to centromeres and the protection of cohesion, whereas the C-terminal kinase domain acts together with Sgo2, the second fission-yeast Shugoshin protein, to promote sister-kinetochore co-orientation during MI. Additional analyses suggest that the protection of centromeric cohesion does not operate when sister kinetochores attach to opposite spindle poles during MI. Sgo1-mediated protection of centromere cohesion might therefore be regulated by the mode of kinetochore attachment.
Vaur
Sabine
S
Centre National de la Recherche Scientifique, Institut de Biochimie et Génétique Cellulaires, Unité mixte de recherche 5095, Bordeaux, F-33077, France.
Cubizolles
Fabien
F
Plane
Guillaume
G
Genier
Sylvie
S
Rabitsch
Peter K
PK
Gregan
Juraj
J
Nasmyth
Kim
K
Vanoosthuyse
Vincent
V
Hardwick
Kevin G
KG
Javerzat
Jean-Paul
JP
D047369:Chromatin Immunoprecipitation; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D020090:Chromosome Segregation / Q000502:physiology*; D049452:Green Fluorescent Proteins; D018386:Kinetochores / Q000378:metabolism; D008540:Meiosis / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism*
D002868:Chromosomal Proteins, Non-Histone; D029702:Schizosaccharomyces pombe Proteins; C485973:Sgo1 protein, S pombe; C485974:Sgo2 protein, S pombe; D049452:Green Fluorescent Proteins; C495594:Bub1 protein, S pombe; D017346:Protein Serine-Threonine Kinases