Protein profiles of the Chinese hamster ovary cells in the resting and proliferating stages
Bibliographic record
Abstract
Identification and characterization of the proteins that regulate the transition from the resting stage (G0) through G1 to S phase of the cell cycle are of central importance to understand the control of cell proliferation and chromosome replication. Unlike in lower organisms, where relatively small numbers of key factors are involved in this process, the factors involved in the same control mechanisms in mammalian systems are much more complex. Furthermore, accumulating lines of evidence now suggest that the nuclear matrix and chromatin organization also play an essential role for the cell cycle control in mammalian cells. To gain a better understanding of the overall dynamics and changes of the protein factors in the context of matrix/chromatin organization, we examined the protein profiles of the Chinese hamster ovary (CHO) cells in different cell cycle compartments. The methods used in this study included subcellular fractionations (cytosol, nuclear extraction, chromatin, and nuclear matrix), two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), silver staining, and immunoblotting. As expected, significant changes of protein profiles were observed when cells entered into proliferating stages from G0. Among approximately 1200 protein spots analyzed by 2-D PAGE, at least 12 showed marked increase or decrease at this transitional period. Further cell-cycle progression from G1 to S phase showed less dramatic changes of overall protein protile. However, the profile of certain proteins showed rather dramatic changes of their subcellular localization during this transitional period. In particular, the levels of proliferating cell nuclear antigen (PCNA) in the nuclear matrix and chromatin dramatically increased in mid-G1 and in the beginning of S phase, respectively, while the overall PCNA level was relatively constant throughout the cell cycle.
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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 | 0.001 | 0.001 |
| 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".