Partitioning of the 2-μm Circle Plasmid of <i>Saccharomyces cerevisiae</i>
Bibliographic record
Abstract
The efficient partitioning of the 2-microm plasmid of Saccharomyces cerevisiae at cell division is dependent on two plasmid-encoded proteins (Rep1p and Rep2p), together with the cis-acting locus REP3 (STB). In addition, host encoded factors are likely to contribute to plasmid segregation. Direct observation of a 2-microm-derived plasmid in live yeast cells indicates that the multiple plasmid copies are located in the nucleus, predominantly in clusters with characteristic shapes. Comparison to a single-tagged chromosome or to a yeast centromeric plasmid shows that the segregation kinetics of the 2-microm plasmid and the chromosome are quite similar during the yeast cell cycle. Immunofluorescence analysis reveals that the plasmid is colocalized with the Rep1 and Rep2 proteins within the yeast nucleus. Furthermore, the Rep proteins (and therefore the plasmid) tend to concentrate near the poles of the yeast mitotic spindle. Depolymerization of the spindle results in partial dispersion of the Rep proteins in the nucleus concomitant with a loosening in the association between plasmid molecules. In an ipl1-2 yeast strain, shifted to the nonpermissive temperature, the chromosomes and plasmid almost always missegregate in tandem. Our results suggest that, after DNA replication, plasmid distribution to the daughter cells occurs in the form of specific DNA-protein aggregates. They further indicate that the plasmid partitioning mechanism may exploit at least some of the components of the cellular machinery required for chromosomal segregation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".