title: Cdc20, a beta-transducin homologue, links RAD9-mediated G2/M checkpoint control to mitosis in Saccharomyces cerevisiae.
abstract: In the budding yeast Saccharomyces cerevisiae, the DNA damage-induced G2 arrest requires the checkpoint control genes RAD9, RAD17, RAD24, MEC1, MEC2 and MEC3. These genes also prevent entry into mitosis of a temperature-sensitive mutant, cdc13, that accumulates chromosome damage at 37 degrees C. Here we show that a cdc13 mutant overexpressing Cdc20, a beta-transducin homologue, no longer arrests in G2 at the restrictive temperature but instead undergoes nuclear division, exits mitosis and enters a subsequent division cycle, which suggests that the DNA damage-induced G2/M checkpoint control is not functional in these cells. This is consistent with our observation that overexpression of CDC20 in wild-type cells results in increased sensitivity to UV irradiation. Overproduction of Cdc20 does not influence the arrest phenotype of the cdc mutants whose cell cycle block is independent of RAD9-mediated checkpoint control. Therefore, we suggest that the DNA damage-induced checkpoint controls prevent mitosis by inhibiting the nuclear division pathway requiring CDC20 function.
authors.affiliation: Institute of Molecular and Cell Biology, National University of Singapore, Singapore.
authors.forename: H H
authors.initials: HH
authors.lastname: Lim
authors.forename: U
authors.initials: U
authors.lastname: Surana
mesh_terms: D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D003470:Culture Media; D004249:DNA Damage; D004271:DNA, Fungal / Q000378:metabolism / Q000528:radiation effects; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D016195:G2 Phase; D005800:Genes, Fungal; D008938:Mitosis; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: C577495:CDC20 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D003470:Culture Media; D004271:DNA, Fungal; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein