Isolation of a cDNA encoding the largest subunit of TFIIA reveals functions important for activated transcription.
Transcription factor IIA has been shown to interact with the TATA-binding protein and to act early during preinitiation complex formation. The human factor is composed of three subunits (alpha, beta, gamma). A human cDNA clone encoding the largest subunit of TFIIA (alpha) was isolated. The recombinant alpha polypeptide, together with the beta and gamma subunits, was capable of reconstituting TFIIA activity. Studies using antibodies raised against recombinant alpha polypeptide demonstrate that TFIIA can be an integral component of the preinitiation complex. We demonstrate that TFIIA not only interacts with TBP but also can associate with the TFIID complex. Functional assays establish that TFIIA has no apparent role in basal transcription but plays an important role in activation of transcription. Interestingly, amino acid sequence analyses of the beta-subunit demonstrate these residues to be entirely contained within the carboxyl terminus of the cDNA clone encoding the alpha-subunit.
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Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635.
Watanabe
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H
Mermelstein
F
F
Admon
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A
Oguri
K
K
Sun
X
X
Wada
T
T
Imai
T
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Shiroya
T
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Reinberg
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D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D035561:Transcription Factor TFIIA; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D011994:Recombinant Proteins; D035561:Transcription Factor TFIIA; D014157:Transcription Factors