Sperm from Mice Genetically Deficient for the PCSK4 Proteinase Exhibit Accelerated Capacitation, Precocious Acrosome Reaction, Reduced Binding to Egg Zona Pellucida, and Impaired Fertilizing Ability1
Bibliographic record
Abstract
The gene for proprotein convertase subtilisin/kexin-like 4 (PCSK4, previously known as PC4) is primarily transcribed in testicular spermatogenic cells. Its inactivation in mouse causes severe male subfertility. To better understand the reproductive function of PCSK4, we examined its subcellular localization in the testicular epithelium via immunohistochemistry, and on intact sperm via indirect immunofluorescence and immunoelectron microscopy. PCSK4 was detected in the acrosomal granules of round spermatids, in the acrosomal ridges of elongated spermatids, and on the sperm plasma membrane overlying the acrosome. We also investigated PCSK4 relevance for sperm acquisition of fertilizing ability by comparing wild-type and PCSK4-null sperm for their abilities in capacitation, acrosome reaction, and egg binding in vitro. PCSK4-null sperm underwent capacitation at a faster rate; they were induced to acrosome react by lower concentrations of zona pellucida; and their egg-binding ability was only half that of wild-type sperm. These sperm physiologic anomalies likely contribute to the severe subfertility of PCSK4-deficient male mice.
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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 | 0.002 |
| 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".