Changes in expression of cell wall turnover genes accompany inhibition of chromosome segregation by bovine protein kinase C α expression in <i>Saccharomyces cerevisiae</i>
Bibliographic record
Abstract
Expression of bovine PKCalpha in Saccharomyces cerevisiae results in growth inhibition, which is strongly augmented upon addition of phorbol esters. To investigate the nature of this PKC-induced inhibition of cell growth, wildtype and bovine PKCalpha-expressing yeast cells were examined by flow cytometry and by fluorescence microscopy after staining with propidium iodide. Upon expression and activation of the mammalian PKC isoform, cells accumulated in the G2/M phase of the cell cycle and exhibited impaired chromsome segregation. In some instances, PKC expression and activation was accompanied by a defect in septum formation between mother and daughter cells. cDNA microarray analysis revealed 4 genes (CTS1, DSE1, DSE2, and SVS1) that changed expression in both a PKCalpha- and phorbol ester-dependent manner. These findings were confirmed by quantitative real-time PCR. Three of these genes are involved in cell wall turnover and are regulated by a single transcription factor (Ace 2) that localizes to daughter cell nuclei after cytokinesis. Taken together, these observations suggest that expression and activation of bovine PKCalpha in yeast cells repress growth by inducing an accumulation of cells in G2/M, likely through an impairment of chromosome segregation, cytokinesis, and septum formation. Moreover, when these observations are taken in the context of previously published observations with various yeast null mutants, we propose that bovine PKCalpha may directly or indirectly activate a subunit of the PP2A phosphatase complex (cdc55), which is a component of the mitotic spindle checkpoint.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".