TFIIB/SUA7(E202G) is an allele-specific suppressor of TBP1(E186D).

The TBP (TATA-box-binding protein), Tbp1p, plays a vital role in all three classes of transcription by RNA polymerases I-III. A TBP1(E186D) mutation had been described that affected interaction of Tbp1p with TFIIB (transcription factor IIB) and that caused slow-growth, temperature-sensitivity, 3-aminotriazole-sensitivity as well as a gal(-) phenotype. We used the ...
TBP1(E186D) mutant for suppressor screens, and we isolated TFIIB/SUA7(E202G) as an allele-specific suppressor of all phenotypes caused by the TBP1(E186D) mutation. Our results show that the SUA7(E202G) mutation restored binding of TFIIB to Tbp1(E186D)p. In addition, we observed that Tbp1(E186D)p was expressed at a lower level than wild-type Tbp1p, and that SUA7(E202G) restored the protein level of Tbp1(E186D)p. This suggested that the TBP1(E186D) mutation might have generated its phenotypes by making Tbp1p the limiting factor for activated transcription. DNA microarray analysis indicated that the TBP1(E186D) temperature-sensitivity and slow-growth phenotypes might have been caused by insufficient amounts of Tbp1p for efficient transcription of the rRNA genes by RNA polymerase I.
Mesh Terms:
Alleles, Aspartic Acid, Basic-Leucine Zipper Transcription Factors, Cell Cycle Proteins, DNA-Binding Proteins, Down-Regulation, Glutamic Acid, Glycine, Mutation, Protein Binding, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, TATA-Box Binding Protein, Temperature, Transcription Factor TFIIB, Transcription Factors
Biochem. J.
Date: Sep. 01, 2007
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