The TATA-binding protein is not an essential target of the transcriptional activators Gal4p and Gcn4p in Saccharomyces cerevisiae

Abstract

According to the recruitment model, transcriptional activators work by increasing the local concentration of one or several limiting factors for the transcription process at the target promoter. The TATA-binding protein Tbp1 has been considered as a likely candidate for such a limiting factor. We have used a series of Gal4p and Tbp1 mutants to correlate the in vivo interaction between the two proteins with the strength of activation. We find a clear correlation between activation strength and in vivo interaction for the series of Gal4p mutants. Consistently, the weaker activator Gcn4p does not interact with Tbp1. However, a corresponding analysis of the series of Tbp1 mutants revealed that Tbp1 is not an essential target of the acidic activators Gal4p and Gcn4p. Furthermore, detailed analysis of a Tbp1 mutant deficient for transcriptional activation by Gal4p revealed that the mutant is defective in interactions with five other proteins involved in the process of transcription.

Improved transcriptional activators and their use in mis‐expression traps in Arabidopsis

“…Although acidic activators share common consensus sequences, their modes of action and potencies can differ. For example the AADs in the yeast and mammalian transcription factors VP16, NK κ B, p53, GCN4, Gal4 and HAP4 differ either in their interactions with TBP, TF II B, TF II A and TF II H (Bongards et al. , 2003; Hall and Struhl, 2002; Mishra et al.…”

“…, 1996). However, activators may also function through other mechanisms, since binding to TBP, the protein most frequently observed to interact with acidic activators, has been shown not to be essential for the function of Gal4 (Bongards et al. , 2003).…”

“…Acidic activation domains have been shown to interact with several components of the RNA polymerase initiation complex: TATA-box-binding protein (TBP) and various TBP-associated factors (TAFs) of TF II D, TF II B, TF II A, TF II H, suppressor of RNA polymerase B (SRB) protein mediators and co-factors (Hall and Struhl, 2002;Hayashi et al, 1998;Matis et al, 2001;Mishra et al, 2003;Nishikawa et al, 1997;Prywes and Zhu, 1992;Shen et al, 1996). However, activators may also function through other mechanisms, since binding to TBP, the protein most frequently observed to interact with acidic activators, has been shown not to be essential for the function of Gal4 (Bongards et al, 2003).…”

Diversity in GeneticIn VivoMethods for Protein-Protein Interaction Studies: from the Yeast Two-Hybrid System to the Mammalian Split-Luciferase System

“…Consequently, the cells become resistant to 5-FOA. While the LexA-VP16 strategy is complementary to the classic two-hybrid system by its application for detection of membrane PPIs, the R-Ura3 method is especially suitable for finding transcription factor partners, both activators and repressors (50,92,372). Furthermore, the ambiguity of Ura3 as a reporter protein permits screening for PPIs and PPI inhibition.…”

The Cyclin in the RNA Polymerase Holoenzyme Is a Target for the Transcriptional Repressor Tup1p in <i>Saccharomyces cerevisiae</i>

“…Srb10p phosphorylates Gal4p, and this phosphorylation is necessary for full activation of the GAL genes by Gal4p [Ansari et al, 2002;Hirst et al, 1999]. Figure 1c shows that an S. cerevisiae strain deleted for SRB10 was unable to grow on galactose plates containing the respiration inhibitor antimycin A (compare top two lanes), just as an S. cerevisiae strain deleted for GAL4 [Bongards et al, 2003]. However, the ¢SRB10 strain expressing N ub -Srb10p was able to grow on these galactose plates ( fig.…”