Immunocytochemical delineation of thyroid hormone receptor beta 2-like immunoreactivity in the rat central nervous system
Autor: | Thomas J. Berrodin, Ronald M. Lechan, Kelly D. Davis, Yanping Qi, Kevin A. Strait, Mitchell A. Lazar, Harold L. Schwartz, Jack H. Oppenheimer |
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Rok vydání: | 1993 |
Předmět: |
Gene isoform
medicine.medical_specialty Transcription Genetic Molecular Sequence Data Biology Rats Sprague-Dawley Thyroid hormone receptor beta Endocrinology Anterior pituitary Antibody Specificity Internal medicine medicine Animals Amino Acid Sequence RNA Messenger Receptor Beta (finance) Peptide sequence Cell Nucleus Messenger RNA Receptors Thyroid Hormone Thyroid hormone receptor Base Sequence Staining and Labeling Immune Sera Brain DNA Immunohistochemistry Rats medicine.anatomical_structure Molecular Probes Triiodothyronine |
Zdroj: | Endocrinology. 132:2461-2469 |
ISSN: | 1945-7170 0013-7227 |
Popis: | The thyroid hormone receptors (TR) are nuclear proteins that include TR alpha and TR beta subtypes, each encoded by a separate gene. Both TR alpha and TR beta give rise to several isoforms of which three, TR alpha 1, TR beta 1, and TR beta 2 bind T3 and mediate the action of thyroid hormone. Although TR beta 2 was initially thought to be confined to the anterior pituitary, we recently observed small quantities of TR beta 2 messenger RNA (mRNA) by polymerase chain reaction analysis of discrete hypothalamic regions. To further examine the distribution of TR beta 2 in the brain, we performed immunocytochemical studies using a highly specific antiserum to TR beta 2, raised against a unique amino acid sequence (TR beta 2[131-145]) that is not present in the other known TRs. This antiserum immunoprecipitated TR beta 2 but not TR alpha 1 or TR beta 1. Immunoreactive TR beta 2 was widely distributed throughout the brain and primarily localized to the cell nucleus. Particularly intense immunostaining was present in the cerebral cortex, cerebellum, and hypothalamus, including regions where TR beta 2 mRNA had not previously been identified. In addition, immunoprecipitation of nuclear extracts with anti-TR beta 2 reduced total T3 binding capacity by approximately 20%, suggesting that immunoreactive TR beta 2 comprises a substantial portion of the total content of nuclear thyroid hormone binding proteins. These studies demonstrate that immunoreactive TR beta 2 is more widely represented in the central nervous system than previously suspected and may play an important role in mediating the action of T3 in many different regions of the brain. The finding of TR beta 2-like material could be due to a disproportionately high ratio of the TR beta 2 translation product and its mRNA in certain regions of the brain, or could indicate the existence of a novel TR beta 2-related protein that is important for T3 binding. |
Databáze: | OpenAIRE |
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