Identification of a mid-anaphase checkpoint in budding yeast.
Activation of a facultative, dicentric chromosome provides a unique opportunity to introduce a double strand DNA break into a chromosome at mitosis. Time lapse video enhanced-differential interference contrast analysis of the cellular response upon dicentric activation reveals that the majority of cells initiates anaphase B, characterized by pole-pole separation, and pauses in mid-anaphase for 30-120 min with spindles spanning the neck of the bud before completing spindle elongation and cytokinesis. The length of the spindle at the delay point (3-4 microm) is not dependent on the physical distance between the two centromeres, indicating that the arrest represents surveillance of a dicentric induced aberration. No mid-anaphase delay is observed in the absence of the RAD9 checkpoint gene, which prevents cell cycle progression in the presence of damaged DNA. These observations reveal RAD9-dependent events well past the G2/M boundary and have considerable implications in understanding how chromosome integrity and the position and state of the mitotic spindle are monitored before cytokinesis.
Yang
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Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA.
Yeh
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Salmon
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Bloom
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D000705:Anaphase; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D002842:Chromatids / Q000502:physiology; D015825:Chromosomes, Fungal / Q000502:physiology* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D017404:In Situ Hybridization, Fluorescence; D007700:Kinetics; D008857:Microscopy, Interference; D018715:Microscopy, Video; D008938:Mitosis; D009024:Morphogenesis; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics; D008941:Spindle Apparatus / Q000502:physiology* / Q000648:ultrastructure
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C069930:rad9 protein