A Role for Sp1 in the Transcriptional Regulation of Hepatic Triacylglycerol Hydrolase in the Mouse
Bibliographic record
Abstract
Microsomal triacylglycerol hydrolase (TGH) hydrolyzes stored triacylglycerol in cultured hepatoma cells (Lehner, R., and Vance, D. E. (1999) Biochem. J. 343, 1-10). We studied expression of TGH in murine liver and found both protein and mRNA increased dramatically at 27 days after birth. Nuclear run-on assays demonstrated that this was due to increased transcription. We cloned 542 base pairs upstream of the transcriptional start site of the murine TGH gene. Electrophoretic mobility shift assays demonstrated enhanced binding of hepatic nuclear proteins from 27-day-old mice to the murine TGH promoter, yielding three differentially migrating complexes. DNase I footprint analysis localized these complexes to two distinct regions: site A contains a putative Sp binding site, and site B contains a degenerate E box. We transfected primary murine hepatocytes with a series of 5'-deletion constructs upstream of the reporter luciferase cDNA. Positive control elements were identified in a segment containing site A. Competitive electrophoretic mobility shift assays and supershift assays demonstrated that site A binds Sp1 and Sp3. Transcriptional activation assays in Schneider SL-2 insect cells demonstrated that Sp1 is a potent activator of the TGH promoter. These experiments directly link increased TGH expression at the time of weaning to transcriptional regulation by Sp1.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".