Profile of H3K27 epigenetic marks in porcine embryos during in vitro development
Bibliographic record
Abstract
Changes in epigenetic marks on the lysine 27 of histone H3 (H3K27) appear to play a key role in lineage determination of mammalian embryos. Genes associated to organogenesis, morphogenesis and embryonic development are temporarily suppressed by trimethylation of H3K27 (H3K27me3) in pluripotent cells. However, the complete profile of epigenetic marks in the H3K27 during early stages of porcine embryo development is not entirely known. The aim of this study was to evaluate the acetylation (H3K27 ac) and methylation (mono-, di- and trimethyl; H3K27 me1, me2 and me3) profile of H3K27 during early development of in vitro-produced (IVP) porcine embryos. Oocytes/embryos (approximately 6 for each mark and developmental stages) were fixed at the following developmental stages: germinal vesicle oocytes (GV), metaphase II oocytes (MII), embryos at pronuclear stage (PN), two cells (2C), four cells (4C), eight cells (8C), D6 blastocysts (D6), and D8 blastocysts (D8). Oocytes/embryos were subjected to an immunofluorescence protocol using rabbit anti-H3K27 ac and anti-H3K27 me1, me2 and me3 primary antibodies (1:1000), and goat anti-rabbit Alexa Flour 488 as a secondary antibody (1:1000). Nuclei were stained with DAPI (10 µg/mL). The fluorescent signal for H3K27 ac was intensive in all developmental stages. H3K27 me1 signal was strong in GV, MII and in only one pronucleus, but the fluorescent signal was weak in 2C, 4C and 8C stage embryos. In D6 and D8 embryos, the H3K27 me1 signal became strong again. The signal for the H3K27 me2 mark was strong in GV and MII stage oocytes, but absent in PN. In embryos at 2C, 4C and 8C stages, the H3K27 me2 signal was very weak or absent, but it was detected again in D6 and D8 embryos. H3K27 me3 was intensely detected in GV, MII and in only one pronucleus. In 2C, 4C, 8C and D6 embryos, the H3K27 me3 signal was very weak or absent. Additionally, 29 D8 blastocysts were subjected to immunofluorescence for detection of H3K27 me3. Of these, 7 did not present any sign of fluorescence, 19 had some or all cells marked and 3 showed H3K27 me3 only in the inner cell mass. The results of this study indicate that the epigenetic marks on the H3K27 are highly dynamic during porcine embryogenesis, which suggests that H3K27 plays an important role in the regulation of gene expression during early embryo development.
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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".