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Isolation and characterization of a cDNA encoding a chicken beta thyroid hormone receptor
M O Showers1, D S Darling, G D Kieffer
1Department of Medicine, Brigham and Women's Hospital, Boston, MA.
DNA and Cell Biology
|April 1, 1991
Summary
Researchers identified a chicken thyroid hormone receptor beta (chTR beta) cDNA. This chTR beta binds thyroid hormone and DNA response elements, and its sequence suggests it may be an alternatively spliced variant.
Area of Science:
- Molecular Biology
- Endocrinology
- Genetics
Background:
- Thyroid hormone receptors (TRs) are crucial nuclear receptors regulating gene expression.
- TR beta isoforms play distinct roles in development and metabolism.
- Understanding TR diversity across species aids in elucidating conserved and divergent functions.
Purpose of the Study:
- To isolate and characterize a cDNA encoding a chicken TR beta homolog.
- To investigate the functional properties and expression patterns of the identified chicken TR beta.
Main Methods:
- Screening of chicken liver cDNA libraries using a rat TR beta-1 cDNA probe.
- DNA sequencing and bioinformatic analysis of isolated cDNA.
- In vitro translation and functional assays for hormone and DNA binding.
- Northern blot analysis for tissue-specific gene expression.
Main Results:
- A cDNA encoding a chicken TR beta (chTR beta) with 96% identity to rat TR beta-1 was isolated.
- The chTR beta protein binds triiodothyronine (T3) with high affinity and recognizes thyroid hormone response elements (TREs).
- A 7.0-kb RNA transcript for chTR beta was detected in multiple tissues, including cerebellum, pituitary, kidney, and liver.
Conclusions:
- The isolated cDNA represents a functional chicken TR beta homolog.
- Sequence variations in untranslated regions suggest chTR beta may be an alternatively spliced product.
- This finding contributes to understanding TR gene regulation and functional diversity in vertebrates.