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Three different thyroid hormone receptor isoforms are detected in a pure culture of ovine oligodendrocytes
Author(s) -
FierroRenoy Juan Francisco,
Szuchet Sara,
Falcone Maria,
Macchia Enrico,
Degroot Leslie
Publication year - 1995
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.440140408
Subject(s) - biology , polyclonal antibodies , thyroid hormone receptor , myelin , gene isoform , microbiology and biotechnology , receptor , medicine , endocrinology , antibody , oligodendrocyte , thyroid , hormone , staining , immunocytochemistry , central nervous system , biochemistry , immunology , genetics , gene
Thyroid hormones are important for the normal development of the central nervous system. In humans, the period around the end of the intrauterine life and the first few months of neonatal life is critically dependent on the presence of normal amounts of thyroid hormone. There are significant events occurring during this time; mydelination is one. Myelin is synthesized by oligodendrocytes. A panel of site‐ specific polyclonal antibodies against α‐1 thyroid hormone receptor (TR), α‐2 variant TR, and β‐1 TR isoforms has been employed to investigate the presence of TR isoforms in a pure culture of ovine oligodendrocytes by the avidin‐biotin peroxidase immunocytochemical method. Strong nuclear staining was obtained with all the anti‐TR antibodies; no reaction products were detected in the cytoplasm or cellular processes. By contrast, an anti myelin basic protein antibody gave strong cytoplasmic and process staining; no nuclear staining was seen. These latter results served to 1) confirm that the cells under study are oligodendrocytes; and 2) prove that the nuclear staining with anti‐TR antibodies is specific. Preimmune sera were totally negative. Scatchard analysis of [ 125 I] T3 binding by isolated oligodendrocyte nuclei demonstrated the existence of high‐affinity low‐capacity T3 binding sites with a K a of ≈ 6 × 10 −9 M and a maximal binding capacity of ≈ 20 fmol/100 μg of DNA. Our results demonstrate that differentiated oligodendrocytes express α‐1 and α‐2 variant and β‐1 isoforms of TR at the protein level and support the notion of a direct impact of thyroid hormones on oligodendrocytes in their regulation of myelin synthesis. © 1995 Wiley‐Liss, Inc.