Genes involved in sister chromatid separation are needed for B-type cyclin proteolysis in budding yeast.
B-type cyclin destruction is necessary for exit from mitosis and the initiation of a new cell cycle. Through the isolation of mutants, we have identified three essential yeast genes, CDC16, CDC23, and CSE1, which are required for proteolysis of the B-type cyclin CLB2 but not of other unstable proteins. cdc23-1 mutants are defective in both entering and exiting anaphase. Their failure to exit anaphase can be explained by defective cyclin proteolysis. CDC23 is required at the metaphase/anaphase transition to separate sister chromatids, and we speculate that it might promote proteolysis of proteins that hold sister chromatids together. Proteolysis of CLB2 is initiated in early anaphase, but a fraction of CLB2 remains stable until anaphase is complete.
Irniger
S
S
Research Institute of Molecular Pathology, Vienna, Austria.
Piatti
S
S
Michaelis
C
C
Nasmyth
K
K
D000705:Anaphase / Q000235:genetics; D064173:Anaphase-Promoting Complex-Cyclosome; D064194:Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics; D002842:Chromatids / Q000235:genetics*; D016213:Cyclins / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics*; D017353:Gene Deletion; D005800:Genes, Fungal / Q000235:genetics*; D008025:Ligases / Q000235:genetics; D008938:Mitosis / Q000235:genetics*; D008954:Models, Biological; D016296:Mutagenesis; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D011233:Precipitin Tests; D029701:Saccharomyces cerevisiae Proteins; D012641:Selection, Genetic; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D015003:Yeasts / Q000235:genetics*
D064194:Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577397:CDC16 protein, S cerevisiae; C577441:CDC23 protein, S cerevisiae; C082274:CSE1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D016213:Cyclins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; C063109:ubiquitin-conjugating enzyme UBC4; D064173:Anaphase-Promoting Complex-Cyclosome; D008025:Ligases