80 DNA METHYLATION OF INSULIN-LIKE GROWTH FACTOR 2 (IGF2) GENE IN DAY 14 IN VITRO-PRODUCED BOVINE EMBRYOS OF DIFFERENT SIZES
Bibliographic record
Abstract
In mammals, a correct DNA methylation reprogramming and the maintenance of genomic imprinting after fertilization are essential for embryo development and pregnancy. One important imprinted gene, related to embryo development and placentation, is the insulin-like growth factor 2 (IGF2) gene. Therefore, embryos with different sizes could show differences in the methylation pattern of IGF2 gene. The aim of this study was to evaluate the methylation pattern of the differentially methylated region (DMR) located within exon 10 of the IGF2 gene, of in vitro-produced Nellore bovine embryos that were different in size on day D14 of development. The embryos were produced from oocytes obtained by follicular aspiration of slaughter house ovaries. On D7 after in vitro fertilization only grade I blastocysts were selected and, in groups of 10 embryos, were transferred non-surgically to the uteri of previously synchronized recipients with similar conditions. Seven days after being transferred, embryos were collected (Day 14 of development) and measured using Motic Images Plus 2.0 program (Motic, Richmond, BC, Canada). Embryos >45 mm were considered large (L) and those <25 mm were considered small (S). After being measured, a portion of each trophoblast layer was biopsied and used to determine the methylation status of the IGF2 gene by bisulfite sequencing. The methylation pattern was evaluated on individual embryos considered as separate replicates. At least 5 to 8 clones were evaluated per embryo and the sequences were analysed with the BiQAnalyser software (Max-Planck-Institut für Informatik, Saarbrücken, Germany), using the GenBank sequence NM_174087.3 as reference. The methylation pattern of the different groups was compared using Kruskal-Wallis test (P < 0.05). No differences in DNA methylation were found between S (26.7 ± 8.3%, n = 37 clones, 5 embryos) and L (34.8 ± 2.9%, n = 20 clones, 4 embryos) embryos. It is already known that the region studied is hypermethylated in sperm and hypomethylated in oocytes and, in some somatic cell types, it is expected to be around 50% methylated, being an imprinted region. Although we found a lower percentage of methylation than that expected for an imprinted region, this pattern may be the physiological pattern for trophoblast cells. This is the first report describing the methylation pattern of this region of the IGF2 gene in Day 14 bovine embryos of different sizes. It can be concluded that the methylation pattern of the intragenic DMR on exon 10 of IGF2 gene of in vitro-produced embryos on Day 14 of development is not affected by embryo size. This work was supported by CNPq, FAP-DF.
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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 | 0.000 |
| 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".