Expression of the Hamster Sperm Protein P26h During Spermatogenesis1
Bibliographic record
Abstract
P26h is a hamster sperm protein of 26 kDa that has been previously characterized as a surface protein covering the acrosome acquired during epididymal transit. P26h is involved in sperm-egg interactions. Recently, it has been shown that the P26h transcript is highly expressed in the testis, and the P26h cDNA has been cloned from a hamster testicular cDNA library. Herein we report the production of a fusion protein (maltose binding protein-P26h) with the whole P26h cDNA encoding sequence and the production of a polyclonal antiserum against it. In Western blots, this antiserum recognized both the P26h extracted from cauda epididymal spermatozoa and the MBP-P26h. We also determined the age of appearance of P26h and which germ cell types express P26h mRNA and its translational product. Northern blots and in situ hybridization analysis showed that P26h transcripts appear at 3 wk of age, within the first round of spermatogenesis in the golden hamster. In situ hybridization showed that P26h transcripts are expressed in spermatocytes and round spermatids, whereas immunostaining revealed the presence of P26h in the cytoplasm of round spermatids and elongated spermatids. P26h was undetectable in testicular spermatozoa. Both in situ hybridization and immunostaining showed P26h expression to be dependent of the testicular cell type and the epithelium cycle. The implications for P26h in sperm-egg interaction and the testicular origin of P26h are discussed.
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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 | 0.001 |
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".