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Glucocorticoid responsiveness conferred by a cloned DNA binding protein
P Luzi1, M Anceschi, D S Strayer
1Department of Pathology, Anatomy, and Cell Biology, Jefferson Medical College, Philadelphia, PA, USA.
Receptor
|January 1, 1995
Summary
Researchers discovered a new protein, "Protein D," that enhances glucocorticoid stimulation of surfactant protein-B (SP-B) expression in lung cells. This finding reveals a novel mechanism for glucocorticoid regulation of SP-B.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Glucocorticoids are known to stimulate surfactant protein-B (SP-B) expression in type II alveolar cells.
- The precise molecular mechanisms underlying this stimulation remain largely unknown.
Purpose of the Study:
- To identify and characterize novel proteins involved in glucocorticoid-mediated regulation of SP-B gene expression.
- To elucidate the role of a newly identified protein (Protein D) in SP-B promoter activity.
Main Methods:
- Protein-DNA binding assays to identify proteins interacting with the SP-B promoter region.
- Cloning and sequencing of the identified DNA-binding protein (Protein D).
- Reporter gene assays (luciferase) in H441 cells to assess the effect of Protein D on SP-B promoter activity under glucocorticoid stimulation.
Main Results:
- A novel 33 kDa DNA-binding protein, designated Protein D, was identified and cloned.
- Protein D binds to an NF1 site on the SP-B promoter (-184 to -198 bp).
- Protein D significantly enhanced SP-B promoter activity in response to dexamethasone (a synthetic glucocorticoid) in H441 cells.
Conclusions:
- Protein D is a novel gene activator that plays a role in glucocorticoid-induced SP-B expression.
- The findings suggest that previously unknown gene activators are involved in glucocorticoid responsiveness of the SP-B gene.
- This discovery provides new insights into the molecular mechanisms regulating lung surfactant production.