Abstract
Although chromosome condensation in the yeast Saccharomyces cerevisiae has been widely studied, visualization of this process in vivo has not been achieved. Using Lac operator sequences integrated at two loci on the right arm of chromosome IV and a Lac repressor-GFP fusion protein, we were able to visualize linear condensation of this chromosome arm during G2/M phase. As previously determined in fixed cells, condensation in yeast required the condensin complex. Not seen after fixation of cells, we found that topoisomerase II is required for linear condensation. Further analysis of perturbed mitoses unexpectedly revealed that condensation is a transient state that occurs before anaphase in budding yeast. Blocking anaphase progression by activation of the spindle assembly checkpoint caused a loss of condensation that was dependent on Mad2, followed by a delayed loss of cohesion between sister chromatids. Release of cells from spindle checkpoint arrest resulted in recondensation before anaphase onset. The loss of condensation in preanaphase-arrested cells was abrogated by overproduction of the aurora B kinase, Ipl1, whereas in ipl1-321 mutant cells condensation was prematurely lost in anaphase/telophase. In vivo analysis of chromosome condensation has therefore revealed unsuspected relationships between higher order chromatin structure and cell cycle control.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adenosine Triphosphatases / metabolism
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Aurora Kinases
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Bacterial Proteins / analysis
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Bacterial Proteins / genetics
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Division
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Chromosome Segregation*
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Chromosomes, Fungal / metabolism
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Chromosomes, Fungal / ultrastructure*
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DNA Topoisomerases, Type II / genetics
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DNA Topoisomerases, Type II / metabolism
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DNA-Binding Proteins / metabolism
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G2 Phase
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Green Fluorescent Proteins / analysis
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Green Fluorescent Proteins / genetics
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Intracellular Signaling Peptides and Proteins
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Lac Repressors
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Mad2 Proteins
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Multiprotein Complexes / metabolism
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Operator Regions, Genetic
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Protein Kinases / genetics
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Protein Kinases / metabolism
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Protein Serine-Threonine Kinases
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Repressor Proteins / analysis
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Repressor Proteins / genetics
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / ultrastructure*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Spindle Apparatus
Substances
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Bacterial Proteins
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Cell Cycle Proteins
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DNA-Binding Proteins
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Intracellular Signaling Peptides and Proteins
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Lac Repressors
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MAD2 protein, S cerevisiae
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Mad2 Proteins
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Multiprotein Complexes
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Nuclear Proteins
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Repressor Proteins
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Saccharomyces cerevisiae Proteins
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condensin complexes
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Green Fluorescent Proteins
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Protein Kinases
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Aurora Kinases
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IPL1 protein, S cerevisiae
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Protein Serine-Threonine Kinases
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Adenosine Triphosphatases
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DNA Topoisomerases, Type II