PMID:5327656

Citation	Bourgeois, S, Cohn, M and Orgel, LE (1965) Suppression of and complementation among mutants of the regulatory gene of the lactose operon of Escherichia coli.J. Mol. Biol. 14:300-2
Abstract	No abstract in PubMed
Links	PubMed
Keywords	Escherichia coli; Genes; Genetic Code; Lactose; Molecular Biology; Mutation
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Main Points of the Paper

• The regulatory gene, i, codes for a protein whereas the operator gene, o, probably does not

Materials and Methods Used

• Parent Strain: Δlac su^-/ Fi^So⁺z⁺y⁺
  • i^S- dominant over i⁺ and not inducible by lactose sz 43
• 5 strains with suppressor mutations
  • su^-
  • su⁺¹
  • su⁺²
  • su⁺³
  • su⁺⁴

Phenotype Annotations

Species	Taxon ID	Strain	Gene (if known)	OMP	Phenotype	Details	Evidence	Notes
Escherichia coli	NCBI:562	Δlac su- /FiSo+z+y+	lacIS	Abolished utilization of carbon source (lactose) Regulation of lac operon expression *Constitutive repression of lac operon expression)	Expression	dominant over i+ and not inducible by lactose unable to utilize lactose		Complementation
Escherichia coli	NCBI:562	Δlac su- /FiSi-o+z+y+	lacIS	Positive suppression Utilization of carbon source (lactose)	Expression	975 lac+ revertants		Suppression
Escherichia coli	NCBI:562	Δlac su- /FiSoCo+z+y+	lacOC	Positive suppression Utilization of carbon source (lactose)	Expression	125 lac+ revertants are now able to utilize lactose
Escherichia coli	NCBI:562	lac+ su+1 /FiSi-o+z+y+	iSi-	Abolished utilization of carbon source (lactose) Regulation of lac operon expression *Constitutive repression of lac operon expression)	Expression	restore the iS phenotype to 10 revertants- giving rise to dominant lac- diploids in i+su+1	Plating Assay	in text, pg. 300
Escherichia coli	NCBI:562	lac+ su+ /FiSi-o+z+y+	iSi-	Abolished utilization of carbon source (lactose) Regulation of lac operon expression *Constitutive repression of lac operon expression)	Expression	restore the iS phenotype in 14 revertants- giving rise to dominant lac- diploids in i+su+1 or su+3	Plating Assay	in text, pg. 300-301
Escherichia coli	NCBI:562	lac+ su+3 /FiSi-774o+z+y+	iSi-774	Inducible expression of beta-galactosidase	Expression	iSi-774 repressor, when suppressed by su+3, becomes inducible	Biochemical Assay	Table 2- beta-galactosidase assay
Escherichia coli	NCBI:562	lac+ su+ /FiSi-o+z+y+	iSi-1058	Abolished utilization of carbon source (lactose) Abolished lactose catabolic process	Expression	unable to utilize lactose-dramatically suppressed by both su+1 and su+3	Biochemical Assay	Table 2- beta-galactosidase assay
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