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The Disruption of the Mitotic Cell Cycle by Inositolless Death in Saccharomyces cerevisiae
Author(s) -
Hanson Barbara Ann,
O'Connor Paul,
Munezero Jean,
Croglio Vincent
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.934.2
Subject(s) - microbiology and biotechnology , mitosis , cyclin dependent kinase , cell cycle , biology , cyclin dependent kinase 1 , programmed cell death , polo like kinase , saccharomyces cerevisiae , cyclin b1 , chemistry , cell , biochemistry , apoptosis , gene
When an inositol‐requiring mutant (MC6A) of Saccharomyces cerevisiae undergoes inositolless death, there is a rapid loss of cell viability. There also is a significant decline in the transcription of CLB2 mRNA levels. CLB2p activates a cyclin‐dependent kinase (CDK) to promote the progression from G2 into the M phase. CDK activity eventually decreases through CLB2 degradation which is caused by the Anaphase‐Promoting Complex (APC). In these cells, the spindle apparatus may form but may not receive the signals to depolymerize at the end of the cycle. To test this idea, changes in polymerized tubulin in the spindle apparatus in these cells were examined by staining the cells with TubulinTracker™ (Oregon Green® 488 Taxol bis‐acetate). Changes in TUB1, CDC28, CDC20, and APC1‐4 mRNA transcription also were measured by RT‐PCR 80 % of the budding cells stained in cells after 24h of inositolless death; however, there was a major increase in the proportion of stained nonbudding cells (54.4%). This was a 2.5 fold increase compared to control cells. The levels of transcribed TUB1 mRNAs also did not decline during inositolless death. The tubulin subunits may be polymerizing to form the spindle apparatus during inositolless death in these cells, but the results suggest that the cellular signals to depolymerize the tubulin may be disrupted because of the reduced levels of CLB2p which affect its degradation by APC.