Kinetochore recruitment of two nucleolar proteins is required for homolog segregation in meiosis I.
Halving of the chromosome number during meiosis I depends on the segregation of maternal and paternal centromeres. This process relies on the attachment of sister centromeres to microtubules emanating from the same spindle pole. We describe here the identification of a protein complex, Csm1/Lrs4, that is essential for monoorientation of sister kinetochores in Saccharomyces cerevisiae. Both proteins are present in vegetative cells, where they reside in the nucleolus. Only shortly before meiosis I do they leave the nucleolus and form a "monopolin" complex with the meiosis-specific Mam1 protein, which binds to kinetochores. Surprisingly, Csm1's homolog in Schizosaccharomyces pombe, Pcs1, is essential for accurate chromosome segregation during mitosis and meiosis II. Csm1 and Pcs1 might clamp together microtubule binding sites on the same (Pcs1) or sister (Csm1) kinetochores.
Rabitsch
Kirsten P
KP
Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, A-1030 Vienna, Austria.
Petronczki
Mark
M
Javerzat
Jean Paul
JP
Genier
Sylvie
S
Chwalla
Barbara
B
Schleiffer
Alex
A
Tanaka
Tomoyuki U
TU
Nasmyth
Kim
K
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002466:Cell Nucleolus / Q000235:genetics* / Q000378:metabolism; D002503:Centromere / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D018386:Kinetochores / Q000378:metabolism*; D046911:Macromolecular Substances; D008540:Meiosis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D000097722:Cohesins
D018528:ATP-Binding Cassette Transporters; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C474335:CSM1 protein, S cerevisiae; C474336:LRS4 protein, S cerevisiae; C490529:MCD1 protein, S cerevisiae; C107004:mam1 protein, S pombe; C077081:REC8 protein, S pombe; D000097722:Cohesins