Activity of the porcine gonadotropin-releasing hormone receptor gene promoter is partially conferred by a distal gonadotrope specific element (GSE) within an upstream enhancing region, two proximal GSEs and a retinoid X receptor binding site
Bibliographic record
Abstract
BACKGROUND: Regulation of gonadotropin-releasing hormone (GnRH) receptor (GnRHR) numbers on gonadotropes within the anterior pituitary gland represents a critical point for control of reproductive function. Binding of GnRH to its receptor regulates follicle stimulating hormone (FSH) and luteinizing hormone (LH) release and levels of this G-protein coupled receptor on the surface of gonadotropes determines their sensitivity to GnRH pulses. While transcriptional regulation of this gene has been studied in mice, rats, humans and sheep, little is known about its regulation in the pig, an important agricultural species and human research model. METHODS: We isolated 5118 bp of 5' flanking sequence for the porcine GnRHR gene and generated luciferase reporter vectors. Deletion and mutation constructs were evaluated in gonadotrope-derived alphaT3-1 cells to determine regions important for gene transcription. Additionally, electrophoretic mobility shift assays (EMSAs) were performed to identify transcription factors binding to the GnRHR promoter. RESULTS: Transient transfections revealed that the GnRHR promoter was functional in alphaT3-1 cells but not in cells of non-gonadotrope origin. Mutation of the highly conserved gonadotrope specific element (GSE) located at -179/-171 of proximal promoter completely ablated luciferase activity, whereas mutation of another GSE at -315/-310 reduced activity by 34%. Consistent with this, EMSAs using alphaT3-1 nuclear extracts and a steroidogenic factor (SF)1 antibody confirmed SF1 binding to both GSEs. EMSAs also demonstrated that a retinoid X receptor (RXR) binding site at -279/-274 binds RXRalpha and RXRbeta and mutation of this site eliminated promoter activity. Transient transfection of alphaT3-1 cells with reporter vectors containing selective removal of 5' flanking region for the porcine GnRHR gene indicated that the -1915/-1431 segment was important for promoter activity. Definition of this region via transfection assays and EMSAs revealed an upstream enhancing region located at -1779/-1667 that increases porcine GnRHR gene expression in alphaT3-1 cells and includes a SF1 binding site at -1760/-1753. CONCLUSIONS: Porcine GnRHR promoter activity in alphaT3-1 cells is partially conferred by a distal GSE, two proximal GSEs and a RXR binding site. Basal gonadotrope expression of the porcine GnRHR gene uniquely involves three GSEs and RXR is newly identified as a regulator of GnRHR promoter activity.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".