Recruitment of TBP or TFIIB to a promoter proximal position leads to stimulation of RNA polymerase II transcription without activator proteins both in vivo and in vitro

• Published in: Biochemical and biophysical research communications Vol. 256; no. 1; pp. 45 - 51
• Main Authors: Huh, J R, Park, J M, Kim, M, Carlson, B A, Hatfield, D L, Lee, B J
• Format: Journal Article
• Language: English
• Published: United States 05.03.1999
• Subjects: AIDS/HIV; Animals; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Enzyme Activation; Female; Fungal Proteins - genetics; Fungal Proteins - metabolism; Genes, Fungal - genetics; Genes, Reporter; HIV-2 - genetics; Kinetics; Oocytes - metabolism; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - metabolism; Response Elements - genetics; RNA Polymerase II - metabolism; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; TATA Box - genetics; TATA-Box Binding Protein; Trans-Activators - physiology; Transcription Factor TFIIB; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic; Transcriptional Activation; Xenopus laevis
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1999.0280

Eukaryotic transcriptional activators may function, at least in part, to facilitate the assembly of the RNA polymerase II (pol II) preinitiation complex at the core promoter region through their interaction with a subset of components of the basal transcription machinery. Previous studies have shown that artificial tethering of TATA-binding protein (TBP) to the promoter region is sufficient to stimulate pol II transcription in yeast. To test whether this phenomenon is a general one in eukaryotic pol II transcription, the DNA-binding domain of yeast GAL4 was fused to either Xenopus laevis TBP or TFIIB in order to enable these factors to be efficiently positioned near the transcription start site in a GAL4-binding site-dependent manner. We found that GAL4-xTBP as well as GAL4-xTFIIB directed an increased level of transcription without involvement of the transcriptional activator, suggesting that incorporation of these basal factors into a preinitiation complex (PIC) is a major rate-limiting step accelerated by activator proteins in metazoans. These results show that transcription activation by artificial recruitment of basal transcription machinery can be observed in general among eukaryotic transcription both in vivo and in vitro. Furthermore, failure of recovery of transcription by adding GAL4-xTFIIB after depletion of endogenous TBP with TATA oligo competitor suggests that recruitment of TBP cannot be bypassed for Pol II transcription.