biostudies-literatureUnknown71(2)Hua SSPrevious results demonstrated that the capR (lon) locus, which is not linked to the gal operon, independently controls the synthesis of the gal operon enzymes and gal mRNA, i.e., galO(+)capR9 strains are derepressed 4- to 6-fold as compared to galO(+)capR(+) strains. A mutation has been isolated and localized in the galactose operator region that defines a new and distinct site of control. Mutation in this site, designated galO(capR+), causes a 4-fold increase in the galactose enzymes, galactokinase (EC 2.7.1.6) and UDP-galactose-4-epimerase (EC 5.1.3.2), in a capR(+) background. These mutants exhibit a reduced response to regulation by the unlinked regulator gene capR (lon). However, the galO(capR+) mutants are still subject to control by the galR repressor, since they can be further dereProceedings of the National Academy of Sciences of the United States of America507-11https://www.ebi.ac.uk/biostudies/studies/S-EPMC388036biostudies-literatureMultiple regulation of the galactose operon-genetic evidence for a distinct site in the galactose operon that responds to capR gene regulation in Escherichia coli K-12.PMC388036Hua SSMarkovitz AfalseMultiple regulation of the galactose operon-genetic evidence for a distinct site in the galactose operon that responds to capR gene regulation in Escherichia coli K-12.Previous results demonstrated that the capR (lon) locus, which is not linked to the gal operon, independently controls the synthesis of the gal operon enzymes and gal mRNA, i.e., galO(+)capR9 strains are derepressed 4- to 6-fold as compared to galO(+)capR(+) strains. A mutation has been isolated and localized in the galactose operator region that defines a new and distinct site of control. Mutation in this site, designated galO(capR+), causes a 4-fold increase in the galactose enzymes, galactokinase (EC 2.7.1.6) and UDP-galactose-4-epimerase (EC 5.1.3.2), in a capR(+) background. These mutants exhibit a reduced response to regulation by the unlinked regulator gene capR (lon). However, the galO(capR+) mutants are still subject to control by the galR repressor, since they can be further dere1974-01-01T00:00:00Z1974 Feb2025-04-18T16:45:16.068Z2025-04-07T04:08:04.273ZS-EPMC388036436094710.1073/pnas.71.2.507