High impact information on SUA7

• Mutations in the Saccharomyces cerevisiae SUA7 gene were isolated as suppressors of an aberrant ATG translation initiation codon in the leader region of the cyc1 gene [1].
• Thus, SUA7 encodes a yeast TFIIB homolog and functions in transcription start site selection [1].
• Molecular and genetic analysis of the cloned SUA7 gene demonstrated that SUA7 is a single copy, essential gene encoding a basic protein (calculated Mr of 38,142) that is homologous to human transcription factor TFIIB [1].
• SSU72 is an essential gene encoding a phylogenetically conserved protein of unknown function that interacts with the general transcription factor TFIIB [2].
• Here we describe a new allele, ssu72-2, that confers a Ts(-) phenotype in a SUA7 wild-type background [2].

Biological context of SUA7

• DNA sequence analysis of the KI-SUA7 gene revealed a 357 amino acid open reading frame that is 67% identical (81% overall similarity) to S. cerevisiae TFIIB [3].
• A plasmid shuffle system was used to replace the essential Sc-SUA7 gene with KI-SUA7 in S.cerevisiae [3].
• We found that controlled SUA7 expression under oxidative conditions occurs at transcriptional and mRNA stability levels [4].
• Therefore, studying SUA7/TFIIB as a potential target of oxidative stress is fundamental [4].
• Synthetic lethality was associated with double sua7 sua8 suppressor mutations, and recessive sua7 mutants failed to fully complement recessive sua8 mutants in heterozygous diploids (nonallelic noncomplementation) [5].

Associations of SUA7 with chemical compounds

• Mutation of glutamate 62 to lysine in yeast transcription factor (TF) IIB (Sua7) causes a cold-sensitive phenotype [6].

Physical interactions of SUA7

• Two portions of this carboxy-terminal region of Fcp1p bound directly to the first cyclin-like repeat in the core domain of the general transcription factor TFIIB, as well as to the RAP74 subunit of TFIIF [7].
• Ino2 interacts physically with the basal transcription factor Sua7 (TFIIB of yeast) [8].

Other interactions of SUA7

• However, in a SUA7+ background, ssu73-1 confers the same upstream shift at ADH1 as an rpb9 null allele [9].
• SOH2 is identical to RPB2, which encodes the second largest subunit of RNA polymerase II, and SOH4 is the same as SUA7, encoding the yeast transcription initiation factor TFIIB [10].
• Because mutations in SOH1, RPB2 and SUA7 suppress the hyperrecombination phenotype of hpr1 mutants, this suggests a link between recombination in direct repeats and transcription [10].
• The sua8 suppressors of Saccharomyces cerevisiae encode replacements of conserved residues within the largest subunit of RNA polymerase II and affect transcription start site selection similarly to sua7 (TFIIB) mutations [5].
• Consistent with its role as a Sua7p import factor, deletion of KAP114 led to specific mislocalization of Sua7p to the cytoplasm [11].

Analytical, diagnostic and therapeutic context of SUA7

• Activity resided in a single polypeptide of approximately 41 kDa, identified by peptide sequence analysis as the product of the SUA7 gene [12].
• A library of sua7 mutations encoding altered forms of yeast TFIIB was generated by error-prone polymerase chain reaction and screened for conditional growth defects [13].

References