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Thyroid-specific enhancer-binding protein (T/EBP): cDNA cloning, functional characterization, and structural identity
K Mizuno1, F J Gonzalez, S Kimura
1Laboratory of Molecular Carcinogenesis, National Cancer Institute, Bethesda, Maryland 20892.
Molecular and Cellular Biology
|October 1, 1991
Summary
Researchers identified a thyroid-specific enhancer-binding protein (T/EBP), identical to thyroid-specific transcription factor 1 (TTF-1). This protein significantly enhances thyroid-specific gene expression by binding to a key enhancer element.
Area of Science:
- Molecular Biology
- Genetics
- Endocrinology
Background:
- Thyroid-specific gene expression is regulated by transcription factors.
- A thyroid-specific enhancer region upstream of the human thyroid peroxidase gene is crucial for gene regulation.
Purpose of the Study:
- To isolate and characterize the transcription factor responsible for thyroid-specific enhancer activity.
- To elucidate the role of this factor in regulating thyroid-specific gene expression.
Main Methods:
- cDNA library screening using a specific DNA probe.
- Nucleotide and amino acid sequencing.
- Gene transfection and reporter gene assays (luciferase).
- Protein expression and purification.
- Gel mobility shift assays.
Main Results:
- Isolation of a cDNA clone for thyroid-specific enhancer-binding protein (T/EBP).
- T/EBP was identified as thyroid-specific transcription factor 1 (TTF-1).
- T/EBP (TTF-1) demonstrated significant thyroid-specific enhancer activity (up to 26-fold) in HepG2 cells.
- Gel mobility shift assays confirmed specific binding of T/EBP (TTF-1) to the enhancer DNA element.
Conclusions:
- T/EBP (TTF-1) is a key regulator of thyroid-specific gene expression.
- The binding of T/EBP (TTF-1) to its specific cis-acting enhancer element is critical for thyroid-specific enhancer activity.