PMID:385587

Citation	Fayerman, JT, Vann, MC, Williams, LS and Umbarger, HE (1979) ilvU, a locus in Escherichia coli affecting the derepression of isoleucyl-tRNA synthetase and the RPC-5 chromatographic profiles of tRNAIle and tRNAVal.J. Biol. Chem. 254:9429-40
Abstract	A mutation in the ilvU locus of Escherichia coli has led to a complex phenotype that included resistance to thiaisoleucine, a loss of derepressibility of isoleucyl tRNA synthetase, and an alteration of the RPC-5 chromatographic profile of the branched-chain aminoacyl-tRNA's. The alterations were manifest in an increase in the amount of Species 2 of both tRNAIle and tRNAVal at the expense of Species 1. A similar alteration, but independent of (and additive to) that caused by the ilvU mutation, was observed upon limitation of either isoleucine or valine. The shift in profile caused by limitation was also independent of the reduced growth rate or the derepression of the isoleucine and valine biosynthetic enzymes that also result from limitation. During chloramphenicol treatment nearly all tRNAIle and tRNAVal formed appears as species 2. Upon recovery from chloramphenicol, Species 2 of both acceptors are converted to Species 1. It is proposed that the ilvU product not only allows derepression of isoleucyl-tRNA synthetase but also retards the conversion of tRNA2Ile to tRNA1Ile and that of tRNA2Val to tRNA1Val. The mutated ilvU loci abolish the derepression and are more efficient in retarding the conversion.
Links	PubMed
Keywords	Amino Acyl-tRNA Synthetases; Chloramphenicol; Chromatography, High Pressure Liquid; Enzyme Repression; Escherichia coli; Genotype; Isoleucine; Isoleucine-tRNA Ligase; Mutation; Phenotype; RNA, Transfer; Valine
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Phenotype Annotations

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Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: CU426 NCBI Taxon ID: 83333	Genotype of Reference Strain: ilvU Genotype of Experimental Strain : ilvU459	Reference Condition:			ECO:0000034	non-traceable author statement	Tiaisoleucine Resistant
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: NCBI Taxon ID: 83333	Genotype of Reference Strain: ilvU Genotype of Experimental Strain : ilvU	Reference Condition:					derepressibility of isoleucyl tRNA synthetase
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: CU210 NCBI Taxon ID: 83333	Genotype of Reference Strain: proA Genotype of Experimental Strain : proA	Reference Condition:					Nitro-4-pyridine N-oxide Resistance
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: CU210 NCBI Taxon ID: 83333	Genotype of Reference Strain: proB Genotype of Experimental Strain : proB	Reference Condition:					Nitro-4-pyridine N-oxide Resistance
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