PMID:14168696

Citation	BECKWITH, JR (1964) A DELETION ANALYSIS OF THE LAC OPERATOR REGION IN ESCHERICHIA COLI.J. Mol. Biol. 8:427-30
Abstract	No abstract in PubMed
Links	PubMed
Keywords	Deletion; Lac; Operator; Escherichia coli; Galactosidases; Genetics; Membrane Transport Proteins; Mutation; RNA, Bacterial; Research; Enzymes; Revertants; Constitutive
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Main Points of the Paper

• The lac operator does not lie in the same region in which o^o mutants are found.

Materials and Methods Used

• Mutant Classes
  • o^c mutants
    • lost the sensitivity to repressor, therefore expressing β-galactosidase constitutively in the presence of the repressor
    • very closely linked to z- mutations mapped at the beginning of the z gene
  • o^o mutants
    • shuts off the production of all 3 enzymic activities of the lac operon

• Types of z^-y⁺ revertants found in the melibiose-agar plate selection
  • Deletions within the lac region
    • abolish basal level of β-galactosidase present in o^o mutants
    • do not further revert to lac⁺ phenotype
  • Mutations at unlinked suppressor loci

Phenotype Annotations

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Species	Taxon ID	Strain	Gene (if known)	OMP	Phenotype	Details	Evidence	Notes
Escherichia coli	NCBI:562	oc		constitutive expression of β-galactosidase in the presence of repressor	Metabolic Activity		Biochemical Assay
Escherichia coli	NCBI:562	oo		constitutive repression of all 3 enzymic activities of the lac operon	Metabolic Activity		Biochemical Assay
Escherichia coli	NCBI:562	oo2-M116		loss of repressibility	Metabolic Activity		Biochemical Assay	Table 1
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