The mechanism of transcriptional synergy of an in vitro assembled interferon-beta enhanceosome.
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.
Kim
T K
TK
Harvard University, Department of Molecular and Cellular Biology, Cambridge, Massachusetts 02138, USA.
Maniatis
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D051698:Activating Transcription Factor 2; D001665:Binding Sites / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000494:pharmacology; D004357:Drug Synergism; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D025741:HMGA1a Protein; D006367:HeLa Cells; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D050856:Interferon Regulatory Factor-1; D016899:Interferon-beta / Q000737:chemistry / Q000235:genetics*; D016350:Leucine Zippers / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism / Q000494:pharmacology; D052002:NF-kappa B p50 Subunit; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000502:physiology*; D051996:Transcription Factor RelA; D035561:Transcription Factor TFIIA; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D019473:Transcription Factors, TFII / Q000378:metabolism / Q000494:pharmacology; D015533:Transcriptional Activation / Q000502:physiology*
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D051996:Transcription Factor RelA; D035561:Transcription Factor TFIIA; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D025741:HMGA1a Protein; D016899:Interferon-beta