The role of CDC28 and cyclins during mitosis in the budding yeast S. cerevisiae.
cdc28-1N is a conditional allele that has normal G1 (Start) function but confers a mitotic defect. We have isolated seven genes that in high dosage suppress the growth defect of cdc28-1N cells but not of Start-defective cdc28-4 cells. Three of these (CLB1, CLB2, and CLB4) encode proteins strongly homologous to G2-specific B-type cyclins. Another gene, CLB3, was cloned using PCR, CLB1 and CLB2 encode a pair of closely related proteins; CLB3 and CLB4 encode a second pair. Neither CLB1 nor CLB2 is essential; however, disruption of both is lethal and causes a mitotic defect. Furthermore, the double mutant cdc28-1N clb2::LEU2 is nonviable, whereas cdc28-4 clb2::LEU2 is viable, suggesting that the cdc28-1N protein may be defective in its interaction with B-type cyclins. Our results are consistent with CDC28 function being required in both G1 and mitosis. Its mitotic role, we believe, involves interaction with a family of at least four G2-specific cyclins.
Surana
U
U
Research Institute of Molecular Pathology, Vienna, Austria.
Robitsch
H
H
Price
C
C
Schuster
T
T
Fitch
I
I
Futcher
A B
AB
Nasmyth
K
K
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D016213:Cyclins / Q000235:genetics / Q000502:physiology*; D004271:DNA, Fungal; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D016153:Genes, Suppressor; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010957:Plasmids; D016133:Polymerase Chain Reaction; D006656:Protamine Kinase / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D012689:Sequence Homology, Nucleic Acid
D016213:Cyclins; D004271:DNA, Fungal; D011494:Protein Kinases; D006656:Protamine Kinase