Disease relevance of tyrR

• Codon usage in the tyrR structural gene shows a bias toward those synonymic codons which are used rarely in efficiently expressed E. coli genes [1].
• Cloning and random mutagenesis of the Erwinia herbicola tyrR gene for high-level expression of tyrosine phenol-lyase [2].

High impact information on tyrR

• Highly purified soluble preparations of truncated TyrR containing residues 1-257 were obtained after the overexpression of a shortened form of the tyrR gene via a specific plasmid construct [3].
• The nucleotide sequence of 1964 base pairs of the Escherichia coli K12 chromosome containing the autogenously regulated regulatory gene tyrR has been determined [1].
• The site of initiation of transcription of tyrR has been mapped by primer-extension analysis, and the initiation codon has been identified by site-specific deletion mutagenesis [1].
• Transcription of aroF and aroG is repressed by the tyrR gene product complexed to tyrosine or phenylalanine, respectively [4].
• The most increased transcription of tpl was observed for the strain with the mutant tyrR allele involving amino acid substitutions of alanine, cysteine, and glycine for valine-67, tyrosine-72, and glutamate-201, respectively [2].

Chemical compound and disease context of tyrR

• A gene locus (linR) responsible for the lincomycin resistance phenotype was mapped at min 30 of the Escherichia coli chromosome near tyrR; it seems to be identical to the previously described linB locus (Apirion, 1967); however, in contrast to these reports it does not seem to alter any ribosomal function [5].

Biological context of tyrR

• The nucleotide sequence of a 22-base pair region adjacent to the promoter and distal to the structural gene exhibits considerable identity with corresponding regions of other genes regulated by tyrR [1].
• These properties were attributed to a mutation in a regulator gene, tyrR (linked to pyr F), that resulted in altered or non-functional aporepressor [6].
• Hence tyrO, tyrA, and aroF constitute an operon regulated by tyrR [6].
• DNA fragments containing the regulatory regions of two genes repressed by the tyrR gene product exhibit retarded electrophoretic mobility in polyacrylamide gels indicating the presence of static bends in the DNA [7].

Associations of tyrR with chemical compounds

• In activation-defective tyrR mutants, expression of mtr is repressed in the presence of tyrosine [8].
• Chromatography of cell extracts on diethylaminoethyl-Sephadex allowed partial separation of two shikimate kinase enzymes and demonstrated that only one of these subject to specific repression control involving tyrR [9].

Other interactions of tyrR

• A comparison between the tyrB operator and those of the other genes belonging to the tyrR regulon is presented [10].
• When the genes were linked in tandem and co-expressed in a plasmid, the relative AroP transport activity of the strain harboring aroP(p) -tyrR (0.95) was significantly lower than that of aroP-tyrR (1.31) [11].

References