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Thyroid hormone receptor alpha(1) regulates expression of the na+/H+ exchanger (NHE1)
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- Author(s) / Creator(s)
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In this paper we examine the role of thyroid hormone in regulating expression of the Na+/H+ exchanger. Thyroid hormone has been reported to regulate the activity of the Na+/H+ exchanger messenger RNA in some cell types. Treatment of cardiac myocytes with 3,5′,3′-triiodothyronine results in an increased expression of Na+/H+exchanger protein. Also, compared with euthyroid animals, hypothyroid rats express decreased amounts of the Na+/H+exchanger protein. To examine the mechanisms involved in regulating expression of the Na+/H+ exchanger, we have characterized the regulation of a distal element of the NHE1 promoter by the thyroid hormone receptor. We have previously shown that a −1085/−800 nucleotide (nt) region of the promoter is a modular element with a −841/−800 nt activating element. Using electrophoretic mobility shift assay, we show that this element interacts with thyroid hormone receptor TRα1, a nuclear hormone receptor. The addition of exogenous TRα increased transcriptional activity of the −841/−800 nt element of the Na+/H+ exchanger promoter. We show that TRα binds to a region on the −841/−800 nt element that is near, but not identical, to the previously identified chicken ovalbumin upstream promoter transcription factor-binding site. Our results are the first demonstration that thyroid hormone and the thyroid hormone receptor TRα1 regulate expression of the Na+/H+ exchanger.
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- Date created
- 2002-01-01
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- Type of Item
- Article (Published)
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- License
- Attribution 4.0 International