Posttranscriptional regulation of oligodendroglial thyroid hormone (T3) receptor beta 1 by T3.
3,5,3'-triiodo-L-thyronine interacts with the genome by binding and activating nuclear 3,5,3'-triiodo-L-thyronine receptors. To determine how in secondary oligodendrocyte cultures, exogenous 3,5,3'-triiodo-L-thyronine influences the expression of different 3,5,3'-triiodo-L-thyronine receptor isoforms, we studied the regulation of alpha 1, alpha 2 and beta 1 3,5,3'-triiodo-L-thyronine receptor mRNAs. In culture, we find that beta 1, 3,5,3'-triiodo-L-thyronine receptor mRNA, but not alpha 1 and alpha 2 3,5,3'-triiodo-L-thyronine receptor mRNAs, is up-regulated by 3,5,3'-triiodo-L-thyronine in a time and dose dependent manner. In addition, we present evidence indicating that beta 1 3,5,3'-triiodo-L-thyronine receptor expression is posttranscriptionally regulated by 3,5,3'-triiodo-L-thyronine. Previous studies from our laboratory and others have shown that in the rat oligodendrocyte lineage, 3,5,3'-triiodo-L-thyronine receptors alpha 1 and alpha 2 were expressed in both early progenitor cells and mature oligodendrocytes. In contrast, beta 1 3,5,3'-triiodo-L-thyronine receptor was found to be expressed only in mature oligodendrocytes. This suggests that thyroid hormone may influence oligodendrocyte differentiation and maturation via 3,5,3'-triiodo-L-thyronine receptor beta 1, which is expressed only in oligodendrocytes and not in progenitor cells. We therefore show that this effect is indirect and is mediated by 3,5,3'-triiodo-L-thyronine which acts posttranscriptionally on the 3,5,3'-triiodo-L-thyronine receptor beta 1 gene.
Baas
D
D
Department of Human Genetics, CHUL, 5Te Foy, Quebec, Canada.
Puymirat
J
J
Sarliève
L L
LL
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology; D009836:Oligodendroglia / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D011988:Receptors, Thyroid Hormone / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D014284:Triiodothyronine / Q000494:pharmacology*
D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine