Transcriptional activation through interaction of MBF2 with TFIIA

Feng Qian Li, Ken Ichi Takemaru, Masahide Goto, Hitoshi Ueda, Hiroshi Handa, Susumu Hirose

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18 Citations (Scopus)

Abstract

Background: Transcriptional activation of the Drosopohila melanogaster fushi tarzu gene by FTZ-F1 or its silkworm counterpart BmFTZ-F1 requires two cofactors MBF1 and MBF2 which do not directly bind to DNA. MBF1 is a bridging molecule that connects FTZ-F1 (or BmFTZ- F1), MBF2 and TATA binding protein TBP. MBF2 is a positive cofactor that activates transcription. Results: To elucidate the mechanism of transcriptional activation by MBF2, we isolated a cDNA coding for the factor. Northern blot analyses showed temporally restricted expression of MBF2 mRNA similar to that of BmFTZ-F1 mRNA. The cDNA sequence predicts a polypeptide of 10 kDa whereas natural MBF2 is a glycoprotein of 22 kDa. The deduced amino acid sequence of the factor showed no homology with proteins in the databases. Farwestern analyses and glutathione S-transferase interaction assays demonstrated that MBF2 makes a direct contact with the β-subunit of TFIIA. In a HeLa cell nuclear extract, bacterially expressed recombinant MBF2 activated transcription from various promoters as natural MBF2 did. This activation requires the MBF2-TFIIA interaction. When recombinant MBF2 was added to the HeLa cell nuclear extract in the presence of MBF1 and FTZ622 bearing the DNA-binding region of FTZ-F1, it selectively activated transcription of the fushi tarazu gene. This selective activation also requires the MBF2-TFIIA interaction. Conclusion: MBF2 activates transcription through its interaction with TFIIA. Selective transcriptional activation occurs when MBF2 is recruited to a promoter carrying the FTZ-F1 binding site by FTZ-F1 and MBF1.

Original languageEnglish
Pages (from-to)143-153
Number of pages11
JournalGenes to Cells
Volume2
Issue number2
Publication statusPublished - 1997
Externally publishedYes

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ASJC Scopus subject areas

  • Cell Biology
  • Genetics

Cite this

Li, F. Q., Takemaru, K. I., Goto, M., Ueda, H., Handa, H., & Hirose, S. (1997). Transcriptional activation through interaction of MBF2 with TFIIA. Genes to Cells, 2(2), 143-153.