Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7B
pubmed:dateCreated
1993-8-19
pubmed:abstractText
The thyroid hormone receptor (TR) belongs to the steroid/nuclear receptor superfamily of ligand-inducible transcription factors. Numerous studies using transient transfection assays have demonstrated that in the absence of thyroid hormone (T3), unliganded TR acts as a constitutive repressor of transcription on genes bearing TR-response elements. We examined the molecular mechanism of TR repression in vitro using both HeLa nuclear extracts and purified basal factors. Here, we show that unliganded TR is an active transcriptional repressor, distinct from passive repressors that compete with activators for DNA binding. Repression by TR can be relieved by adding the T3 analog triiodothyroactic acid, suggesting that liganded TR undergoes a conformational change that masks or disrupts the repressor function. Repression by TR is mediated through the basal transcription machinery and can occur independently of previously characterized TATA-binding protein-associated cofactors thought to be involved in either basal repression or activator-dependent transcription. TR inhibits transcription at an early step during preinitiation complex (PIC) assembly, as preassembled PICs are refractory to the inhibitory effects of TR.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0890-9369
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1400-10
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:8392477-Animals, pubmed-meshheading:8392477-Baculoviridae, pubmed-meshheading:8392477-Base Sequence, pubmed-meshheading:8392477-DNA, pubmed-meshheading:8392477-Growth Hormone, pubmed-meshheading:8392477-HeLa Cells, pubmed-meshheading:8392477-Humans, pubmed-meshheading:8392477-Mice, pubmed-meshheading:8392477-Molecular Sequence Data, pubmed-meshheading:8392477-Moths, pubmed-meshheading:8392477-Promoter Regions, Genetic, pubmed-meshheading:8392477-Rats, pubmed-meshheading:8392477-Receptors, Cell Surface, pubmed-meshheading:8392477-Receptors, Retinoic Acid, pubmed-meshheading:8392477-Receptors, Thyroid Hormone, pubmed-meshheading:8392477-Retinoid X Receptors, pubmed-meshheading:8392477-Transcription, Genetic, pubmed-meshheading:8392477-Transcription Factors, pubmed-meshheading:8392477-Triiodothyronine
pubmed:year
1993
pubmed:articleTitle
Unliganded thyroid hormone receptor inhibits formation of a functional preinitiation complex: implications for active repression.
pubmed:affiliation
Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't