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.
Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore.
Boon Shang
BS
Chew
Norbert
N
Lehming
D000483:Alleles; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D018698:Glutamic Acid / Q000235:genetics / Q000378:metabolism*; D005998:Glycine / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D035181:TATA-Box Binding Protein / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D035581:Transcription Factor TFIIB / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D050976:Basic-Leucine Zipper Transcription Factors; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C052130:GAL4 protein, S cerevisiae; C501391:GCN4 protein, S cerevisiae; C115017:SPT15 protein, S cerevisiae; C073680:SUA7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D035581:Transcription Factor TFIIB; D014157:Transcription Factors; D001224:Aspartic Acid; D018698:Glutamic Acid; D005998:Glycine