Detailed profiles of histone modification in male germ line cells of the young and aged mice
Bibliographic record
Abstract
Human epidemiological studies have shown paternal aging as one of the risks for neurodevelopmental disorders such as autism in offspring. A recent study has suggested that factors other than de novo mutations due to aging can influence biology of offspring. Here we are focusing on epigenetic alterations in sperm that can influence offspring developmental programs. In this study, we qualitatively and semi-quantitatively evaluated histone modification patterns in male germ line cells throughout spermatogenesis based on immunostaining of testes taken from young (3 months) and aged (12 months) old mice. Although localization patterns were not obviously changed between young and aged testes, some histone modification showed differences in their intensity. Among histone modifications that repress gene expression, H3K9me3 was decreased in the male germ line cells in the aged testis, while H3K27me2/3 was increased. The intensity of H3K27ac, an active mark, was relatively low in the aged testis. Interestingly, H3K27ac was detected in putative sex chromosomes of round spermatids, while other chromosomes were occupied by a repressive mark H3K27me3. Among other histone modifications that activate gene expression, H3K4me2 was drastically decreased in the male germ line cells in the aged testis. H3K79me3 was contrastingly increased and accumulated on the sex chromosomes at M-phase spermatocytes. Therefore, aging induced alterations in the amount of histone modifications, of which patterns were different in individual histone modifications. Moreover, histone modification seems to be differentially regulated by aging on the sex chromosomes and on others. These findings would help elucidate epigenetic mechanisms underlying influence of paternal aging on offspring's development.
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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 | 0.001 | 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".