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Sequence and expression of a functional chicken progesterone receptor
O M Conneely1, A D Dobson, M J Tsai
1Department of Cell Biology, Baylor College of Medicine, Texas Medical Center, Houston 77030.
Molecular Endocrinology (Baltimore, Md.)
|August 1, 1987
Summary
Researchers cloned and sequenced chicken progesterone receptor cDNA, revealing multiple mRNA variants. The functional receptor activates gene transcription in a progesterone-dependent manner.
Area of Science:
- Molecular Biology
- Endocrinology
- Genetics
Background:
- The progesterone receptor (PR) is a crucial nuclear receptor involved in various physiological processes.
- Understanding the molecular mechanisms of PR action requires detailed characterization of its gene and protein products.
Purpose of the Study:
- To clone and sequence the cDNA encoding the chicken progesterone receptor.
- To investigate the different mRNA species and their encoded polypeptides.
- To functionally characterize the cloned chicken progesterone receptor.
Main Methods:
- cDNA cloning and sequencing of the chicken progesterone receptor.
- Analysis of mRNA species in chick oviduct cells using Northern blotting and direct cDNA sequencing.
- Expression of the cloned receptor in progesterone receptor-negative Cos M-6 cells.
- Hormone binding assays and antibody reactivity tests.
- Functional assays to measure transcriptional activation of a target gene.
Main Results:
- A 4.5 kilobase (Kb) cDNA encoding the chicken progesterone receptor was cloned and sequenced.
- The complete cDNA contains an open reading frame of 2361 nucleotides, encoding a 787 amino acid polypeptide (85.9 K mol wt).
- At least four distinct mRNA species were detected, with variations in 3'-untranslated regions and one producing a truncated polypeptide lacking hormone-binding and DNA-binding domains.
- The expressed polypeptide in Cos M-6 cells showed indistinguishable hormone binding and antibody reactivity compared to oviduct PR.
- The cloned receptor demonstrated progesterone-dependent transcriptional activation of a target gene with high specificity and potency.
Conclusions:
- The chicken progesterone receptor cDNA has been successfully cloned and sequenced.
- Multiple mRNA variants exist, potentially leading to different receptor isoforms with distinct functions.
- The cloned chicken progesterone receptor is a functional protein capable of mediating progesterone-dependent gene transcription.