Suppression of oocyte glycine transporter activity in mouse cumulus–oocyte complexes before resumption of meiosis
Bibliographic record
Abstract
Glycine is a key regulator of cell volume in early preimplantation mouse embryos and supports embryo viability. Its accumulation is initiated when the GLYT1 glycine transporter (SLC6A9) is activated in oocytes at about the same time the oocyte is released from meiotic arrest at the germinal vesicle (GV) stage. The mechanism by which GLYT1 is maintained in an inactive state before ovulation is triggered is unknown. Here, we have shown that GLYT1 activity can remain suppressed in isolated cumulus-oocyte complexes (COCs) under defined culture conditions that include keeping COCs physically separated and using the physiological mediator of GV arrest, natriuretic peptide precursor C. When GV arrest is instead maintained in oocytes within COCs by inhibiting phosphodiesterase 3A or cyclin-dependent kinase 1, GLYT1 similarly remains inactive. However, GLYT1 becomes activated in isolated GV oocytes similarly maintained in GV arrest, indicating that cumulus cells are required for suppressing GLYT1 activity. This implies that meiotic arrest is necessary but not sufficient for preventing GLYT1 activation and that an inhibitory factor likely arising from the cumulus is also required. Finally, we have found that pyrrophenone, a selective inhibitor of arachidonic acid production by cytoplasmic phospholipase A alpha, causes GLYT1 to become activated in oocytes within COCs despite maintenance of meiotic arrest of the oocyte. Since arachidonic acid levels decrease in oocytes after release from GV arrest, we propose that arachidonic acid may be a candidate for the inhibitory factor in COCs that regulates GLYT1 activity.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".