A delay in the Saccharomyces cerevisiae cell cycle that is induced by a dicentric chromosome and dependent upon mitotic checkpoints.
Dicentric chromosomes are genetically unstable and depress the rate of cell division in Saccharomyces cerevisiae. We have characterized the effects of a conditionally dicentric chromosome on the cell division cycle by using microscopy, flow cytometry, and an assay for histone H1 kinase activity. Activating the dicentric chromosome induced a delay in the cell cycle after DNA replication and before anaphase. The delay occurred in the absence of RAD9, a gene required to arrest cell division in response to DNA damage. The rate of dicentric chromosome loss, however, was elevated in the rad9 mutant. A mutation in BUB2, a gene required for arrest of cell division in response to loss of microtubule function, diminished the delay. Both RAD9 and BUB2 appear to be involved in the cellular response to a dicentric chromosome, since the conditionally dicentric rad9 bub2 double mutant was highly inviable. We conclude that a dicentric chromosome results in chromosome breakage and spindle aberrations prior to nuclear division that normally activate mitotic checkpoints, thereby delaying the onset of anaphase.
Neff
M W
MW
Department of Biology, University of Virginia, Charlottesville 22901.
Burke
D J
DJ
D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins; D015825:Chromosomes, Fungal; D004171:Diploidy; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000235:genetics; D008938:Mitosis; D006656:Protamine Kinase / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins
C070351:BUB2 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; D006656:Protamine Kinase