New Controlling Element in the Lac Operon of E. coli

Ippen, Karin; Miller, Jeffrey H; Scaife, John; Beckwith, Jonathan

doi:10.1038/217825a0

Cited by 132 publications

(50 citation statements)

References 8 publications

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“…The amidase specific activities after overnight growth in pyruvate medium were about 5 % of that of the parent strain. This is similar to that obtained for P-galactosidase for certain promotor mutants of the lac operon of Escherichia coli in which the rate of initiation of transcription of lac mRNA is very low (Ippen et al 1968). Three of the acetamide-negative mutants from Am idase promo tor mutants 95 …”

Section: Isolation Of Catabolic Repression-resistant Mutants From Jlusupporting

confidence: 65%

Catabolite Repression of Pseudomonas aeruginosa Amidase: Isolation of Promotor Mutants

Smyth

Clarke

1975

Journal of General Microbiology

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S U M M A R YAmong mutants of Pseudomonas aeruginosa isolated from fluoroacetamide medium were some which synthesized amidase at about 5 % of the rate of the parent constitutive strain, PAC 10 I . Seven fluoroacetamide-resistant mutants with low amidase activity gave rise to secondary mutant strains on succinate + butyramide plates. One appeared to be an 'up-promotor' mutant and synthesized amidase at a high rate. This mutant, PAC433, was not stimulated by cyclic-AMP and was much less sensitive to catabolite repression by succinate. The mutation conferring resistance to catabolite repression was cotransduced at a frequency of 96 % (26/27) with the amidase genes umiR, amiE. Five other revertants had catabolite repression-resistance mutations which were linked to the amidase genes and these also were probably promotor mutants. One strain had a mutation conferring resistance to catabolite repression which was unlinked to the amidase genes. I N T R O D U C T I O NThe inducible amidase of Pseudomonus ueruginosa is subject to catabolite repression by succinate and other carbon compounds. Synthesis of the enzyme by inducible and constitutive strains is stimulated by cyclic AMP (c-AMP) which also gives partial relief to the mild repression produced by compounds such as lactate (Smyth & Clarke, 1975). Catabolite repression-resistant mutants isolated from plates containing lactamide as nitrogen source and succinate as carbon source (S/L plates) carried mutations which were unlinked to the amidase genes amiRdrniE. It was thought that if c-AMP affected the initiation of transcription, as in Escherichid coli, it should be possible to isolate a class of promotor mutants which would be resistant to catabolite repression and insensitive to stimulation of amidase synthesis by c-AMP. The amidase structural gene dmiE is known to be closely linked to the amidase regulator gene amiR, since mutations in these genes are cotransduced at frequencies > 90 % (Brammar, Clarke & Skinner, 1967). With promotor mutants it would be predicted that the mutations conferring resistance to catabolite repression would be cotransduced with the amiE gene at frequencies approaching IOO %. METHODSBacterial StrditIS and media. The strains used in this study were from P. aeruginosa PACI and are listed in Tables I to 3 Growth conditions and enzyme assays were as in Smyth & Clarke (1975).

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Section: Isolation Of Catabolic Repression-resistant Mutants From Jlusupporting

confidence: 65%

Catabolite Repression of Pseudomonas aeruginosa Amidase: Isolation of Promotor Mutants

Smyth

Clarke

1975

Journal of General Microbiology

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“…Galactokinase, tryptophanase, a histidine-induced protein, and a phenylalanine degrading enzyme were found to be at least as sensitive to NF as was 13-galactosidase (Table 1) Because the NF-sensitive genes all are catabolite repressible (11), our first thought was that NF might interfere in the promotor activation by adenosine 3':5'-cyclic monophosphate (cAMP) + cAMP receptor protein (CAP) (11,12). In mutants of adenylate cyclase or CAP, fl-galactosidase synthesis should then be NF-resistant. There are two ways of measuring 13-galactosidase synthesis in these mutants: (i) a basal rate of lac transcription is observed even in the absence of the CAP regulation (13,14). (ii) A cAMP-CAP independent promotor mutation can be used (15,16 (17) and subsequently induced.…”

Section: Inhibition Of Bacterial Growth and Of Macromolecule Synthesimentioning

confidence: 99%

Nitrofurans, a group of synthetic antibiotics, with a new mode of action: discrimination of specific messenger RNA classes.

Herrlich¹,

Schweiger²

1976

Proc. Natl. Acad. Sci. U.S.A.

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Nitrofurans, a class of antibacterial drugs in, extensive use, interferes with gene expression in a highly specific manner. While in the low dose range (0.5-25 ;&g/ml), 5-nitro-2-furfurylidene-l-aminohydantoin has no effect on transcription, it inhibits specifically the expression of one class of genes in translation. The specific inhibition concerns the inducible genes. The inhibition of messenger RNA expression occurs at the initiation step. The action of nitrofurans, thus, indicates heterogenei in e population of mRNA molecules and in the translational machinery, and suggests the possibility of selective translational control.

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“…The active cAMP-CAP complex exerts its effects on lac transcription in the region excised by the Li deletion (3,4). The P-mutant L8 maps in the CAP-sensitive site (23). duced into other strains by selecting for transfer of the adjacent tonB-locus.…”

mentioning

confidence: 99%

A Mutant Transcription Factor That is Activated by 3′:5′-Cyclic Guanosine Monophosphate

Sanders

McGeoch

1973

Proc. Natl. Acad. Sci. U.S.A.

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We report here the isolation of an extragenic suppressor of a promoter mutation in the lactose operon of Escherichia coli. Genetic data have indicated that the suppressor of the P-mutation maps in the structural gene for the transcription factor catabolite activator protein. Biochemical studies suggest that the mutant molecules of catabolite activator protein are altered in such a way that they are activated by 3':5'-cyclic GMP in addition to their normal effector, 3':5'-cyclic AMP.

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New Controlling Element in the Lac Operon of E. coli

Cited by 132 publications

References 8 publications

Catabolite Repression of Pseudomonas aeruginosa Amidase: Isolation of Promotor Mutants

Catabolite Repression of Pseudomonas aeruginosa Amidase: Isolation of Promotor Mutants

Nitrofurans, a group of synthetic antibiotics, with a new mode of action: discrimination of specific messenger RNA classes.

A Mutant Transcription Factor That is Activated by 3′:5′-Cyclic Guanosine Monophosphate

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