Studies on the repression of basal transcription (silencing) by artificial and natural human thyroid hormone receptor-beta mutants.


Journal Article

Thyroid hormone receptors (TRs) are ligand-dependent transcription factors that regulate target gene transcription. Interestingly, in the absence of ligand, TRs also can repress basal transcription of positively regulated target genes, suggesting that unliganded TR may have a distinct role in gene regulation. In this paper, DNA binding, truncation, and natural human TR beta mutants were used in cotransfection and electrophoretic mobility shift assays to study various aspects of TR-mediated basal repression. Presently, little is known about the role(s) of natural human TR beta mutants on basal repression. These results show that: 1) TR binding to DNA likely is required for basal repression; 2) the amino-terminal region of TR is not required for basal repression; 3) TR homodimer binding is not absolutely required for basal repression, as TR mutants that selectively form TR-retinoid X receptor heterodimers can mediate basal repression; and 4) TR mutants with poor T3-binding affinity likely have constitutive basal repression, even in the presence of ligand. These findings provide new insight on the mechanism of basal repression by unliganded TRs.

Full Text

Duke Authors

Cited Authors

  • Yen, PM; Wilcox, EC; Hayashi, Y; Refetoff, S; Chin, WW

Published Date

  • July 1995

Published In

Volume / Issue

  • 136 / 7

Start / End Page

  • 2845 - 2851

PubMed ID

  • 7789309

Pubmed Central ID

  • 7789309

International Standard Serial Number (ISSN)

  • 0013-7227

Digital Object Identifier (DOI)

  • 10.1210/endo.136.7.7789309


  • eng

Conference Location

  • United States