Publications by authors named "Amit C J Vas"

3 Publications

  • Page 1 of 1

Monitoring the DNA Topoisomerase II Checkpoint in Saccharomyces cerevisiae.

Methods Mol Biol 2018 ;1703:217-240

Department of Genetics, Cell Biology & Development, University of Minnesota, 420 Washington Ave SE, Minneapolis, MN, 55455, USA.

Topoisomerase II activity is crucial to maintain genome stability through the removal of catenanes in the DNA formed during DNA replication and scaffolding the mitotic chromosome. Perturbed Topo II activity causes defects in chromosome segregation due to persistent catenations and aberrant DNA condensation during mitosis. Recently, novel top2 alleles in the yeast Saccharomyces cerevisiae revealed a checkpoint control which responds to perturbed Topo II activity. Described in this chapter are protocols for assaying the phenotypes seen in top2 mutants on a cell biological basis in live cells: activation of the Topo II checkpoint using spindle morphology, chromosome condensation using fluorescently labeled chromosomal loci and cell cycle progression by flow cytometry. Further characterization of this novel checkpoint is warranted so that we can further our understanding of the cell cycle, genomic stability, and the possibility of identifying novel drug targets.
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http://dx.doi.org/10.1007/978-1-4939-7459-7_16DOI Listing
July 2018

Assaying topoisomerase II checkpoints in yeast.

Methods Mol Biol 2009 ;582:167-87

Department of Genetics, University of Minnesota, Minneapolis, MN, USA.

Topoisomerase II activity is crucial to maintain genome stability through the removal of catenanes in the DNA formed during DNA replication and scaffolding the mitotic chromosome. Perturbed Topo II activity causes defects in chromosome segregation due to persistent catenations and aberrant DNA condensation during mitosis. Recently, novel top2 alleles in the yeast Saccharomyces cerevisiae revealed a checkpoint control that responds to perturbed Topo II activity. Described in this chapter are protocols for assaying the phenotypes seen in top2 mutants on a cell biological basis in live cells: activation of the Topo II checkpoint using spindle morphology, chromosome condensation using fluorescently labeled chromosomal loci, and cell cycle progression by flow cytometry. Further characterization of this novel checkpoint is warranted so that we can further our understanding of the cell cycle, genomic stability, and the possibility of identifying novel drug targets.
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http://dx.doi.org/10.1007/978-1-60761-340-4_14DOI Listing
January 2010

In vivo analysis of chromosome condensation in Saccharomyces cerevisiae.

Mol Biol Cell 2007 Feb 6;18(2):557-68. Epub 2006 Dec 6.

Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455, USA.

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.
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http://dx.doi.org/10.1091/mbc.e06-05-0454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1783779PMC
February 2007