Dominant alleles of Saccharomyces cerevisiae CDC20 reveal its role in promoting anaphase.
We identified an allele of Saccharomyces cerevisiae CDC20 that exhibits a spindle-assembly checkpoint defect. Previous studies indicated that loss of CDC20 function caused cell cycle arrest prior to the onset of anaphase. In contrast, CDC20-50 caused inappropriate cell cycle progression through M phase in the absence of mitotic spindle function. This effect of CDC20-50 was dominant over wild type and was eliminated by a second mutation causing loss of function, suggesting that it encodes an overactive form of Cdc20p. Overexpression of CDC20 was found to cause a similar checkpoint defect, causing bypass of the preanaphase arrest produced by either microtubule-depolymerizing compounds or MPS1 overexpression. CDC20 overexpression was also able to overcome the anaphase delay caused by high levels of the anaphase inhibitor Pds1p, but not a mutant form immune to anaphase-promoting complex- (APC-)mediated proteolysis. CDC20 overexpression was unable to promote anaphase in cells deficient in APC function. These findings suggest that Cdc20p is a limiting factor that promotes anaphase entry by antagonizing Pds1p. Cdc20p may promote the APC-dependent proteolytic degradation of Pds1p and other factors that act to inhibit cell cycle progression through mitosis.
Schott
E J
EJ
Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Hoyt
M A
MA
D000483:Alleles; D000595:Amino Acid Sequence; D000705:Anaphase / Q000502:physiology*; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics*; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005799:Genes, Dominant / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D017386:Sequence Homology, Amino Acid
C577495:CDC20 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; C578004:PDS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; C093416:MPS1 protein, S cerevisiae