p66shc, but not p53, is involved in early arrest of in vitro-produced bovine embryos
Bibliographic record
Abstract
High embryo loss occurs in the first week of bovine embryo development, with a high percentage of embryonic arrest. We hypothesized that arrested embryos enter a 'senescence-like state' and that both the cell cycle regulatory protein p53 and the stress-related protein p66(shc), which are involved in the onset of senescence in somatic cells, are responsible for this early embryonic arrest. In our in vitro production system, 13.5 +/- 0.5% of embryos arrest at the 2-4-cell stage. First cleavage occurs between 26 and 48 h post insemination (hpi), with early cleaving embryos showing only 0.6 +/- 0.3% arrest, with later cleaving embryos exhibiting up to 14.2 +/- 0.9% arrest. We compared 2-4-cell embryos collected at 28 hpi with those arrested at the 2-4-cell stage collected at day 8 post insemination. Quantification by real-time PCR and by semi-quantitative immunofluorescence showed significantly higher p66(shc) mRNA and protein levels in both arrested and late cleaving embryos versus 28 hpi embryos. By comparison, no significant changes in p53 mRNA, protein and phosphorylation levels were detected. Taken together, these results demonstrate that embryonic developmental potential is related to the time of first cleavage and that p66(shc), but not p53, is up-regulated in early arrested in vitro-produced bovine embryos.
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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".