High impact information on SUP4

• The TFIIIB-dependent binding of pol III to the SUP4 tRNA and 5S rRNA genes has been analyzed in binary (protein and DNA only) and precisely arrested ternary (protein, DNA, and RNA) transcription complexes [1].
• Mutations at the yeast SUP4 tRNATyr locus: DNA sequence changes in mutants lacking suppressor activity [2].
• Yeast strains harboring indepjendent mutations within the SUP4 tyrosine tRNA gene have been selected by virtue of their inactivating effect upon the SUP4-o UAA suppressor [2].
• Here we show that in vitro transcription of the yeast SUP4 tRNATyr gene in crude yeast extracts is strongly stimulated by tyrosyl-tRNA synthetase (TyrRS) but not by two other non-cognate synthetases [3].
• The strand specificity as well as the repair heterogeneity determined in the transcribed strand of the SUP4 gene, correlate well with the previously reported site- and strand-specific mutagenesis in this gene [4].

Biological context of SUP4

• The orientation of the cyc1 gene could not be clearly deduced from the behavior of the distal marker SUP4 in wild-type recombinants that arose from diploids heteroallelic for cyc1 mutations [5].
• Crossing over and coconversion data from tetrad analysis established the gene order to be centromere-cyc1-rad7-SUP4 [5].
• One of these mutants has been mapped to chromosome X, 31 cM distal to SUP4, and defines a new locus designated STE18 [6].
• To investigate the role of TBP-DNA interactions in tRNA gene transcription, we generated sequence substitutions in the SUP4 tRNATyr gene TFIIIB binding site [7].
• Analysis of DNA sequences encompassing the regions of highly mutable sites for all three genes indicated that the mutable sites are at the bases of potential hairpin structures; this type of structure could not be found at any of the other, less mutable G . C runs in SUP4, CYC1, and HIS4 [8].

Associations of SUP4 with chemical compounds

• Highly mutable sites for ICR-170-induced frameshift mutations are associated with potential DNA hairpin structures: studies with SUP4 and other Saccharomyces cerevisiae genes [8].
• The structure of the Saccharomyces cerevisiae RNA polymerase III transcription complex on the SUP4 tRNATyr gene was probed at distances of approximately 10 to approximately 23 A from the C-5 methyl of thymidine in the major groove of DNA using photoreactive aryl azides attached to deoxyuridine by variable chain lengths [9].
• Tagetitoxin inhibition of in vitro transcription of the yeast SUP4 and SUP6 tRNA(Tyr) genes demonstrates template dependence and indicates that inhibition may occur after UMP incorporation [10].
• The S. cerevisiae RNA polymerase III (pol III) transcription factor TFIIIB binds to DNA upstream of the transcription start site of the SUP4 tRNA(Tyr) gene in a TFIIIC-dependent reaction and to the major 5S rRNA gene in a reaction requiring TFIIIC and TFIIIA [1].
• To explore the possibility that these oligonucleotides are released by the action of the RNA polymerase III nuclease at previously observed uridine-rich pause sites, we tested modified templates lacking the arrest sites present in the SUP4 tRNATyr gene [11].

Physical interactions of SUP4

• Derivatives of the Saccharomyces cerevisiae SUP4 tRNATyr gene with binding sites for the transcription regulatory protein GCN4 located upstream of the transcriptional start site have been constructed [12].

Other interactions of SUP4

• Sequence data are presented for the Saccharomyces cerevisiae TAP1 gene and for a mutant allele, tap1-1, that activates transcription of the promoter-defective yeast SUP4 tRNA(Tyr) allele SUP4A53T61 [13].
• These data, together with previous studies of Ty1 integration positions at CAN1 and SUP4, indicate that the rad6 effect on Ty1 target-site selection is not gene specific [14].
• Also cdc8 appeared to be distal to SUP4 on the basis of crossovers that were associated with conversion of SUP4 [5].
• Disruption of the genomic copy of STP1 resulted in a reduced efficiency of SUP4-mediated suppression and the accumulation of pre-tRNAs [15].
• CEP1 was mapped and found to reside on chromosome X, 2.0 centimorgans from SUP4 [16].

Analytical, diagnostic and therapeutic context of SUP4

• HO activity was assessed by three bioassays: a mating-type switch, extinction of expression of an a-specific reporter gene, and the appearance of Canr Ade- papillae resulting from excision of an engineered Ty element containing the HO-endonuclease target site and a SUP4 degrees gene [17].
• Synthetic oligodeoxynucleotide primers, based on the consensus Alu sequence, and the Sup4 DNA fragment in the YAC arms were used to amplify end-specific DNA sequences by the polymerase chain reaction (PCR) for screening of the linking YAC recombinant clones ("YAC-Alu PCR") [18].

References