Binding of AP-2 and ETS-Domain Family Members Is Associated with Enhancer Activity in the Hypersensitive Site III Region of the Human Growth Hormone/Chorionic Somatomammotropin Locus
Bibliographic record
Abstract
The human GH gene family is specifically expressed in somatotrophs of the anterior pituitary and placental syncytiotrophoblast. Two nuclease-hypersensitive sites, HS III and HS V, are associated with a region of chromatin located 28 and 30 kb upstream of the pituitary GH gene transcription initiation site (+1) in both pituitary and placenta nuclei. A role for this region in pituitary GH gene expression has been reported, but the potential relevance to placental gene expression has not been determined. Deletion analysis of a 5.2-kb region (nucleotides - 27,568/-32,746) containing HS III to V-related sequences localized significant enhancer activity to a 574-bp HS III fragment (nucleotides -27,676/-28,249) in multiple transfected cell lines. Four nuclease-protected regions [footprints (FP) 1-4] were identified in the 574-bp fragment. FP2 and FP3 were detected with placenta cell nuclear protein, whereas FP1 and FP4 were observed with placental and nonplacental cell nuclear extract. Disruption of FP1 had no effect on heterologous promoter activity in transfected pituitary and placental cells, whereas loss of FP2 and FP3 resulted in modest increases in placental cells, reflecting the presence of repressor activity associated with these regions in vitro. In contrast, disruption of the FP4 region by mutation or deletion significantly reduced enhancer activity. As a result, 30-fold enhancer activity was localized to a 41-bp region in transfected placental tumor cells. Binding of candidate proteins, activator protein (AP)-2 (FP3) and Elk-1 (FP4), was confirmed using competition assays with specific oligonucleotides and antibodies. Moreover, these factors were associated with the hyperacetylated HS III region in human pituitary [activator protein 2 (AP-2) and Elk-1] and term placenta (AP-2) chromatin. These data implicate AP-2 and ETS-domain family members in the regulation of the GH/CS locus and raise the possibility that different complexes form in the HS III region in placenta and pituitary cells.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".