Disease relevance of tyrT

• The tyrT locus of E. coli contains a 208 bp spacer region that separates two copies of sequence encoding tRNATyr1 [1].
• The genes coding for tRNA1Tyr (tyrT) comprise two mature structural sequences separated by a 200 bp "intergenic spacer." It is known that in transducing phage, the region adjoining the CCA end of the second mature structural sequence comprises a 178 bp repeated sequence which contains an in vitro, rho-dependent transcriptional termination site [2].

High impact information on tyrT

• The parallel between the tyrT and TyrU gene clusters is discussed in relation to dual function transcripts that specify both tRNA and protein [1].
• Aminoacylation of tRNA(CUA)Tyr [tyrT (UAG)] by GlnRS-D235H resulted in a 4-fold increase in the Km for the Gln, which was reduced to a 2-fold increase when A73 was replaced with G73 [3].
• We demonstrate here that on saturation of its three binding sites in the UAS, FIS forms a specific nucleoprotein complex which 'traps' RNA polymerase (RNAP) at the promoter of the tyrT operon [4].
• We have found that initiation of RNA synthesis at the tyrT promoter of Escherichia coli can be stimulated on a plasmid by a factor of 4-6 by elevation of DNA supercoiling in vivo [5].
• The Escherichia coli DNA bending protein factor for inversion stimulation (FIS), is neither necessary nor responsible for the stimulation of transcription from the wild type promoter for the tyrT operon (encoding a species of tyrosine tRNA) that occurs upon resumption of exponential growth [6].

Chemical compound and disease context of tyrT

• While the Escherichia coli Su-3 (tyrT) tyrosine tRNA suppressor inserts only tyrosine at amber codons in E. coli, we show here that in Saccharomyces cerevisiae this tRNA inserts leucine and no significant amounts of any other amino acid [7].
• We analysed induction and repair of UV induced pyrimidine dimers in the Escherichia coli tRNA gene tyrT [8].
• The tyrT locus of Escherichia coli exhibits a regulatory function for glycine metabolism [9].

Biological context of tyrT

• This conclusion is unexpected given that the regulatory element required for optimal transcription of tyrT contains three binding sites for FIS protein [6].
• Four of the five different mutant tyrT promoters have alterations at positions that might have been expected from DNA sequence studies with other prokaryote promoters [10].
• The kinetics of the interactions of polymerase alone with the tyrT promoter differ from those observed previously at the lacUV5 promoter [11].
• Fusions of the lac operon to the transfer RNA gene tyrT of Escherichia coli [12].
• Use of gene fusions to isolate promoter mutants in the transfer RNA gene tyrT of Escherichia coli [13].

Associations of tyrT with chemical compounds

• However, tyrT transcription is stimulated in a FIS-dependent manner both in vivo and in vitro when promoter function is impaired by mutation of the promoter itself or by the addition of the polymerase effector guanosine 5'-diphosphate 3'-diphosphate [6].
• The reactivity of the 160 bp tyrT DNA fragment towards diethyl pyrocarbonate (DEPC) has been investigated in the presence of bis-intercalating quinoxaline antibiotics and the synthetic depsipeptide TANDEM [14].
• Finally, it is shown that the presence or absence of the tyrT terminator upstream from the lambda tR1 terminator does not affect the efficiency of transcription at termination lambda tr1 [15].
• Hydroxyl radicals, generated by allowing an iron (II).EDTA complex to react with hydrogen peroxide, have been employed to cleave the 160-base pair tyrT DNA fragment in the presence and absence of the minor groove-binding antibiotics netropsin and distamycin A [16].

References