Study of Gene Expression in Bovine Granulosa Cells from Different Follicle Growth Phases.
Bibliographic record
Abstract
It is known that 1 in 3 follicles contains a good a competent oocyte, but to this day the features of those particular follicles have not been characterized. The objective of this study was to build the transcriptomic profile of granulosa cells (GC's) originating from pre-dominance follicle (6 to 9mm diameter) in dairy cattle using microarrays and validating by Q-PCR. Granulosas originating from three different phases of antral follicle growth were compared: growing (G), plateau (P) and atresia (A), as categorized by flow cytometry on DNA content. The growing and atretic conditions we're each hybridized against the plateau condition as a reference in order to understand the specific biological mechanisms underway in this class of follicles, which is believed to hold oocytes with the best capacities to produce an offspring following in-vitro assisted reproduction technologies such as maturation (MIV) and fertilisation (FIV). 2,942 genes were differentially expressed (P<0.05) in G vs P and 1,974 in P vs A. Ingenuity Pathway Analysis (IPA) software was used to study the regulation pattern of genes and functions predicted to be enriched in the dataset. Cytometry was efficient in categorizing the follicles in the different phases, as determined by the down-regulation of steroidogenesis genes: cytochrome P450, subfamily XIX (CYP19A1, i.e. aromatase), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (HSD3B1) and cytochrome P450, family 11, subfamily A, polypeptide 1 (CYP11A1) in the granulosa cells of P follicles relative to G and probably in response to the decreasing FSH level. On the other hand, the P vs A contrast showed up-regulation of multiple transcripts associated to apoptosis: tissue transglutaminase (TGM2; transglutaminase 2 (C polypeptide, protein-glutamine-gamma-glutamyltransferase)), SH3 domain containing ring finger 1(SH3RF1, also known as POSH), disabled-2 (DAB2), desmoglein-2 (DSG2), death receptor 5 (DR5), caspase-4 (CASP4), Ras association (RalGDS/AF-6) domain family member 1 (RASSF1), chaperonin containing TCP1, subunit 2 (beta) (CCT2) and interferon regulatory factor 5 (IRF5). Functions such as cell death, secretion of lipids and ploidy of cells, were predicted to be increased in P-follicle-granulosa compared to G-follicles, while functions such as growth of cells were predicted to be decreased in P relative to G. Although the genes more expressed in the A condition did not correspond to common atretic markers, they are likely to be indicators differentiating between the late atresia status of the follicle and early atresia, a hallmark characteristic of plateau follicles. This study offers multiple candidate genes to be further studied at a biochemical level in order to elucidate their role in the modulation of oocyte competence. This work was supported by NSERC of Canada.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".