An activation-specific role for transcription factor TFIIB in vivo

Wei-Hua Wu, Michael Hampsey

    Research output: Contribution to journalArticle

    40 Scopus citations

    Abstract

    A yeast mutant was isolated encoding a single amino acid substitution [serine-53 → proline (S53P)] in transcription factor TFIIB that impairs activation of the PHO5 gene in response to phosphate starvation. This effect is activation-specific because S53P did not affect the uninduced level of PHO5 expression, yet is not specific to PHO5 because Adr1-mediated activation of the ADH2 gene also was impaired by S53P. Pho4, the principal activator of PHO5, directly interacted with TFIIB in vitro, and this interaction was impaired by the S53P replacement. Furthermore, Pho4 induced a conformational change in TFIIB, detected by enhanced sensitivity to V8 protease. The S53P replacement also impaired activation of a lexA((op))-lacZ reporter by a LexA fusion protein to the activation domain of Adr1, thereby indicating that the transcriptional effect on ADH2 expression is specific to the activation function of Adr1. These results define an activation-specific role for TFIIB in vivo and suggest that certain activators induce a conformational change in TFIIB as part of their mechanism of transcriptional stimulation.

    Original languageEnglish (US)
    Pages (from-to)2764-2769
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume96
    Issue number6
    DOIs
    StatePublished - Mar 16 1999

    Keywords

    • PHO5
    • Pho4
    • SUA7
    • Transcriptional control

    ASJC Scopus subject areas

    • General

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