1: Mol Cell. 1998 Jan;1(2):277-87. 

Recruitment of CBP/p300 by the IFN beta enhanceosome is required for synergistic
activation of transcription.

Merika M, Williams AJ, Chen G, Collins T, Thanos D.

Department of Biochemistry and Molecular Biophysics, Columbia University, New
York, New York 10032, USA.

Transcriptional activation of the IFN beta gene in response to virus infection
requires the assembly of an enhanceosome, consisting of the transcriptional
activators NF-kappa B, IRF1, ATF2/c-Jun, and the architectural protein HMG I(Y).
The level of transcription generated by all of these activators is greater than
the sum of the levels generated by individual factors, a phenomenon designated
transcriptional synergy. We demonstrate that this synergy, in the context of the
enhanceosome, requires a new protein-protein interaction domain in the p65
subunit of NF-kappa B. Transcriptional synergy requires recruitment of the
CBP/p300 coactivator to the enhanceosome, via a new activating surface assembled
from the novel p65 domain and the activation domains of all of the activators.
Deletion, substitution, or rearrangement of any one of the activation domains in
the context of the enhanceosome decreases both recruitment of CBP and
transcriptional synergy.

PMID: 9659924 [PubMed - indexed for MEDLINE]


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2: Mol Cell. 1997 Dec;1(1):119-29. 

The mechanism of transcriptional synergy of an in vitro assembled
interferon-beta enhanceosome.

Kim TK, Maniatis T.

Harvard University, Department of Molecular and Cellular Biology, Cambridge,
Massachusetts 02138, USA.

A functional interferon-beta gene enhanceosome was assembled in vitro using the
purified recombinant transcriptional activator proteins ATF2/c-JUN, IRF1, and
p50/p65 of NF-kappa B. Maximal levels of transcriptional synergy between these
activators required the specific interactions with the architectural protein HMG
I(Y) and the correct helical phasing of the binding sites of these proteins on
the DNA helix. Analyses of the in vitro assembled enhanceosome revealed that the
transcriptional synergy is due, at least in part, to the cooperative assembly
and stability of the complex. Reconstitution experiments showed that the
formation of a stable enhanceosome-dependent preinitiation complex require
cooperative interactions between the enhanceosome; the general transcription
factors TFID, TFIIA, and TFIIB; and the cofactor USA. These studies provide a
direct biochemical demonstration of the importance of the structure and function
of natural multicomponent transcriptional enhancer complexes in gene regulation.

PMID: 9659909 [PubMed - indexed for MEDLINE]


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