PMID:6178725

Citation	Ryals, J, Hsu, RY, Lipsett, MN and Bremer, H (1982) Isolation of single-site Escherichia coli mutants deficient in thiamine and 4-thiouridine syntheses: identification of a nuvC mutant.J. Bacteriol. 151:899-904
Abstract	A method is described to rapidly select and classify many independent near-UV irradiation-resistant Escherichia coli mutants, which include tRNA modification and RNA synthesis control mutants. One class of these mutants was found to be simultaneously deficient in thiamine biosynthesis and in the ability to modify uridine in tRNA to 4-thiouridine, known to be the target for near-UV irradiation. These mutants were found to be unable to make thiazole, a thiamine precursor. The addition of thiazole restores the thiamine deficiency but does not render the cells near-UV irradiation sensitive. In vitro studies on one of these mutants indicated a deficiency in protein factor C (nuvC), required for the 4-thiouridine modification of tRNA. In P1 transduction, the thiazole marker cotransduced with the histidine marker, which places the thiazole marker between 42 and 46 min on the E. coli chromosome map. Both thiamine production and 4-thiouridine production were resumed by 87% of the spontaneous reversions, suggesting a single-point mutation. Our results indicate that we have isolated nuvC mutants and that the nuvC polypeptide is involved in two functions, tRNA modification and thiazole biosynthesis.
Links	PubMed
Keywords	Chromosome Mapping; Chromosomes, Bacterial; Escherichia coli; Genes, Bacterial; Mutation; RNA, Bacterial; RNA, Transfer; Thiamine; Thiazoles; Thiouridine; Ultraviolet Rays
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Main Points of the Paper

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Materials and Methods Used

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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: 1157-4 NCBI Taxon ID: 83333	Genotype of Reference Strain: phoE Genotype of Experimental Strain : phoE+	Reference Condition:					Acid resistance.
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