PABP Interacting Protein 2 (Paip2) Is a Major Translational Regulator Involved in the Maturation of Male Germ Cells and Male Fertility.
Bibliographic record
Abstract
Paip2 regulates translation by promoting the dissociation of PABP (PolyA Binding Protein) from the poly(A)tails of mRNA. There are 2 homologs of Paip2,Paip2A and Paip2B, that are highly expressed in the pancreas. In the testis, Paip2A is highly expressed whereas Paip2B levels are low. During spermatogenesis, mRNAs are stored in the male germ cells as transcription is active until early spermiogenesis in round spermatids. Translation is tightly regulated during spermiogenesis since, in the absence of any transcriptional activity, several proteins are only expressed at very specific steps. Some mechanisms by which translation is regulated during the late phase of spermatogenesis have been suggested but this remains unclear. Using immunohistochemistry, we have shown that Paip2A and PABP are both specifically expressed in the testicular germ cells showing an overlapping expression during spermiogenesis. Paip2A is expressed in spermatids from steps 7-8 of spermiogenesis until the sperm are released. PABP starts to be expressed in the pachytene spermatocytes at stages 5 and its expression increases gradually in the round spermatids, to finally disappear in the elongating spermatids at step 15 of spermiogenesis. In order to understand the role of Paip2 in spermatogenesis and male fertility, we characterized a double knock-out (DKO) transgenic mouse lineage in which both Paip2A and Pai2B genes were inactivated. By continuous mating with wild type (wt) partners, we showed that DKO females presented normal fertility whereas DKO male mice were infertile. When compared to wt males, the DKO males had a 6% lower body weight as well as significantly lower epididymal (25% less) and prostatic weights (71% less). No spermatozoa could be found in the cauda epididymidis and the testis sperm head count was significantly decreased by 64%. Histological examination of the testes revealed abnormalities with vacuolization in some tubules and abnormal alignment of the spermatozoa at the lumen at stages 7-8, thus suggesting that the elongated spermatids in the DKO mouse are retained and cannot be released into the lumen properly. Moreover, we have shown an abnormal expression of PABP in the single Paip2A knock-out male germ cells where PABP is still expressed in elongated spermatids at stage 8 and staining can be found in the lumen all along the epididymis. We hypothesize that Paip2 translation factors are major players in the development of male germ cells, regulating the translation of key proteins involved in chromatin condensation and sperm release during spermiogenesis. Supported by CIHR. (platform)
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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 | 0.000 | 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) | 0.000 | 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".