Transcriptional regulation by nuclear hormone receptors is thought to involve interactions with putative cofactors that may potentiate receptor function. Here we show human thyroid alpha purified from HeLa cells grown in the presence of (T3) associated a group distinct proteins termed receptor-associated (TRAPs). In an vitro system reconstituted general initiation factors and (and absence added T3), "liganded" (TR)/TRAP complex markedly activates transcription promoter template containing...

Cognate cDNAs are described for 2 of the 10 thyroid hormone receptor-associated proteins (TRAPs) that immunopurified with receptor α (TRα) from ligand-treated HeLa (α-2) cells. Both TRAP220 and TRAP100 contain LXXLL domains found in other nuclear receptor-interacting both appear to reside a single complex TRAPs (in absence TR). However, only shows direct ligand-dependent interaction TRα, these interactions mediated through C terminus TRα (at least part) TRAP220. also interacts receptors...

J D Fondell, A L Roy, and R G Roeder Laboratory of Biochemistry Molecular Biology, Rockefeller University, New York, York 10021.

Coactivators previously implicated in ligand-dependent activation functions by thyroid hormone receptor (TR) include p300 and CREB-binding protein (CBP), the steroid coactivator-1 (SRC-1)-related family of proteins, multicomponent TR-associated (TRAP) complex. Here we show that two positive cofactors (PC2 PC4) derived from upstream stimulatory activity (USA) cofactor fraction act synergistically to mediate (T 3 )-dependent either TR or a TR-TRAP complex an vitro system reconstituted with...

Transcriptional coactivators implicated in gene activation by the thyroid hormone receptor (TR) include members of p160/steroid coactivator (SRC) family proteins, p300, and multisubunit TR-associated protein (TRAP)/Mediator complex. We investigated temporal recruitment these cofactors to mammalian (T3)-responsive promoters vivo . show that upon T3 treatment, TR recruits all three types specific at least two sequential steps: p160/SRC proteins p300 are recruited first rapidly induce histone...

ABSTRACT The obligate intracellular bacterium Chlamydia has a unique developmental cycle that alternates between two contrasting cell types. With hardy envelope and highly condensed genome, the small elementary body (EB) maintains limited metabolic activities yet survives in extracellular environments is infectious. After entering host cells, EBs differentiate into larger proliferating reticulate bodies (RBs). Progeny are derived from RBs late stages eventually exit cells. How expression of...

Unliganded human thyroid hormone receptor alpha (hTR alpha) can repress transcription by inhibiting the formation of a functional preinitiation complex (PIC) on promoters bearing (TR)-binding elements. Here we demonstrate that hTR directly contacts TATA-binding protein (TBP) and preincubation with TBP completely alleviates TR-mediated repression in vitro. Using stepwise preassembled PICs, show targets either TBP/TFIIA or TBP/TFIIA/TFIIB steps PIC assembly for repression. We also domain maps...

The TRAP coactivator complex is a large, multisubunit of nuclear proteins which associates with hormone receptors (NRs) in the presence cognate ligand and stimulates NR-mediated transcription.A single subunit, TRAP220, thought to target entire liganded receptor through domain containing two signature LXXLL motifs shown previously other types be essential for mediating NR binding.In this work, we demonstrate that each LXXLL-containing regions, termed binding domains 1 2 (RBD-1 RBD-2),...

The human thyroid hormone receptor-associated protein (TRAP)-Mediator complex was originally identified as a large multimeric that copurifies with the receptor (TR) from HeLa cells and markedly enhances TR-mediated transcription in vitro. More recent studies have implicated TRAP-Mediator coactivator for broad range of nuclear receptors well other classes transcriptional activators. Here we present evidence plays functional role androgen (AR)-mediated transcription. We show several subunits...

Abstract Androgen receptor (AR) signaling pathways are important for the survival and proliferation of prostate cancer cells. Because AR activity is facilitated by distinct coregulatory factors complexes, it conceivable that some these proteins might also play a role in promoting oncogenesis. The multisubunit Mediator complex an coactivator broad range regulatory transcriptional including AR, yet its unclear. Here, we used RNA interference to knock down expression two integral components,...

Mediator is a multisubunit assemblage of proteins originally identified in humans as coactivator bound to thyroid hormone receptors (TRs) and essential for (T3)-dependent transcription. Cyclin-dependent kinase 8 (CDK8), cyclin C, MED12, MED13 form variably associated subcomplex (termed the CDK8 module) whose functional role TR-dependent transcription remains unclear. Using vitro cellular approaches, we show here that complexes containing module are specifically recruited into preinitiation...

Mediator is a conserved multisubunit complex that acts as functional interface between regulatory transcription factors and the general RNA polymerase II initiation apparatus. MED1 pivotal component of binds to nuclear receptors broad array other gene-specific activators. Paradoxically, found in only fraction total cellular complexes, mechanisms regulating its binding core remain unclear. Here, we report phosphorylation by mitogen-activated protein kinase-extracellular signal-regulated...

The numerous members of the steroid/nuclear hormone receptor superfamily act as direct transducers circulating signals, such steroids, thyroid hormone, and vitamin or lipid metabolites, modulate transcription specific target genes, primarily dimeric complexes. receptors for 9-cis retinoic acid 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], RXR VDR, respectively, this superfamily, form a heterodimeric complex bind cooperatively to D responsive elements (VDREs) activate repress multitude genes which...

Thyroid hormone receptors (TRs) are ligand-regulated transcription factors that bind to thyroid response elements of target genes. Upon ligand binding, they recruit coactivator complexes increase histone acetylation and RNA polymerase II (Pol II) activate transcription. Recent studies suggest nuclear coactivators may have temporal recruitment patterns on elements, yet little is known about the nature at multiple endogenous We thus performed chromatin immunoprecipitation assays investigate...

MED1 is a key coactivator of the androgen receptor (AR) and other signal-activated transcription factors. Whereas overexpressed in prostate cancer cell lines thought to coactivate distinct target genes involved cell-cycle progression castration-resistant growth, underlying mechanisms by which becomes its oncogenic role clinical have remained unclear. Here, we report that epithelium clinically localized human patients, correlated with elevated cellular proliferation. In Nkx3.1:Pten mutant...