What question did this study set out to answer?

To determine whether the proximal promoter or the far-upstream enhancer regulates the liver-specific expression and hormonal responsiveness of the carbamoyl-phosphate synthetase I gene.

October 1, 1995Journal of Biological ChemistryOpen Access

The Far-upstream Enhancer of the Carbamoyl-phosphate Synthetase I Gene Is Responsible for the Tissue Specificity and Hormone Inducibility of Its Expression

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Population

Primary rat hepatocytes, hepatoma cells (FTO-2B), and fibroblasts

Design

Preclinical

Authors

VCVincent M. ChristoffelsElectrophysiology MHMaurice J.B. van den HoffPediatric / Congenital Cardiology AMAntoon F.M. MoormanPediatric / Congenital Cardiology

Discussion

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Implication

Does not inform clinical decisions; leaves open whether this enhancer drives CPS expression in human tissues or disease models.

Key Points

To determine whether the proximal promoter or the far-upstream enhancer regulates the liver-specific expression and hormonal responsiveness of the carbamoyl-phosphate synthetase I gene.
Conducted transient transfection reporter assays in primary rat hepatocytes, FTO-2B hepatoma cells, and fibroblasts using wild-type and mutated promoter-enhancer constructs.
Tested a 469-base-pair enhancer located 6 kilobases upstream paired with either the native carbamoyl-phosphate synthetase I promoter or a minimal thymidine kinase promoter.
The proximal promoter exhibited uniform activity across hepatocytes, hepatoma cells, and fibroblasts, demonstrating that it does not confer tissue-specific transcription.
A 469-base-pair upstream enhancer drove strong, hormone-dependent, hepatocyte-specific transcription, with point mutations in its cyclic AMP- and glucocorticosteroid-responsive elements heavily impairing hormone induction.
Interaction assays showed that enhancer-mediated activation depends on both the TATA box and an adjacent GAG box motif within the proximal promoter.

Structured PICO

Population

Primary rat hepatocytes, hepatoma cells (FTO-2B), and fibroblasts

Intervention

Transient transfection assays with constructs containing the proximal promoter, far-upstream enhancer, and 5'-untranslated region of the carbamoyl-phosphate synthetase I (CPS) gene

Outcome

Gene expression and promoter/enhancer activitysurrogate

The far-upstream enhancer of the CPS gene, rather than the proximal promoter, is responsible for its tissue-specific and hormone-inducible expression.

Cite This Study

Christoffels et al. (1995) studied this question.

synapsesocial.com/papers/6a914123b167dec8df2e50d0 https://doi.org/10.1074/jbc.270.42.24932

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The Far-upstream Enhancer of the Carbamoyl-phosphate Synthetase I Gene Is Responsible for the Tissue Specificity and Hormone Inducibility of Its Expression

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The Far-upstream Enhancer of the Carbamoyl-phosphate Synthetase I Gene Is Responsible for the Tissue Specificity and Hormone Inducibility of Its Expression

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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