Characterization of Strong Polar Mutations in a Region Immediately Adjacent to the
            <scp>l</scp>
            -Arabinose Operator in
            <i>Escherichia coli</i>
            B/r

Eleuterio, Marianne; Griffin, Barbara E.; Sheppard, David E.

doi:10.1128/jb.111.2.383-391.1972

Cited by 9 publications

(9 citation statements)

References 35 publications

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“…If the catabolite-hypersensitive mutants prove to define the region of the initiator region where CAP-cAMP interacts, then the initiator must contain at least three subregions, one for binding of ribonucleic acid polymerase, one for araC gene activator, and one for the binding of the CAP-cAMP complex. A group of ara mutants with the properties of down-promoter mutants have been described previously (4). The effects of these mutations and their reversions upon catabolite repression may prove to be useful in the further elucidation of the relationships between these three regions.…”

Section: Resultsmentioning

confidence: 99%

“…Media. In addition to those previously described (2,4,15), the following media were employed: mineral base plus 0.2% i-arabinose, 0.2% -glucose. and 0.2% glycerol, as described (M-Ara-Glu-GIc); EMB plus 1% L-arabinose and 1% D-glucose (EMB-Ara-Glu).…”

Section: Methodsmentioning

confidence: 99%

“…Two attempts were made to determine the genetic location of the mutations causing hypersensitivity to catabolite repression. (i) P1 transducing phage prepared on strains RG1400 (ara+), RG0829 (ara-9802), and RG0603 (ara-9602) were used to transduce ME1453 (araBIOC768) (a deletion that covers a portion of the araB and araC genes as well as the entire initiator and operator regions [4] to Ara+). Transductants were subjected to one, single-colony isolation and assayed 0for Larabinose isomerase activity in the presence of Dglucose.…”

Section: Methodsmentioning

confidence: 99%

“…In the lac operon, mutants have been isolated that carry lesions in the promoter region (a region in many ways comparable to the initiator region of the ara operon [4,15]) and are insensitive to catabolite repression (12,(17)(18)(19). This has been taken as evidence that the promoter region is the site of action of the CAP-cAMP complex in the lac operon.…”

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confidence: 99%

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Mutations in the l -Arabinose Operon of Escherichia coli B/r That Result in Hypersensitivity to Catabolite Repression

Gendron

Sheppard

1974

J Bacteriol

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Two independent mutants resistant to L-arabinose inhibition only in the presence of D-glucose were isolated from an L-arabinose-sensitive strain containing the araD139 mutation. Preliminary mapping studies indicate that these mutations are closely linked to the araIOC region. Addition of D-glucose to growing cultures of these mutants results in a 95 to 98% repression of ara operon expression, as compared to a 50% repression of the parental control. Since cultures of both mutant and parental strains undergo a 50% repression of lac operon expression upon addition of glucose, the hypersensitivity to catabolite repression exhibited by these mutants is specific for the ara operon. Addition of cyclic adenosine monophosphate reverses the catabolite repression of the ara operon in both mutant and parent strains to 70 to 80% of the control. It is suggested that in these mutants the affinity of the ara operon initiator region for the cAMP-catabolite-activator protein complex may have been altered. 417 on August 2, 2020 by guest

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Mutations in the l -Arabinose Operon of Escherichia coli B/r That Result in Hypersensitivity to Catabolite Repression

Gendron

Sheppard

1974

J Bacteriol

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“…1) consists ofthree structural genes, araB, araA, and araD, coding for L-ribulokinase, Larabinose isomerase, and L-ribulose-5-phosphate-4-epimerase, respectively (9). The expression of these structural genes is controlled by a cis acting regulatory region araOI (6,7,9,18) and a diffusible product specified by gene araC (14,18). Gene araC is controlled independently of the structural genes (21).…”

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confidence: 99%

Mutations in the L-arabinose operon of Escherichia coli B/r with reduced initiator function

Gonzalez¹,

Sheppard²

1977

J Bacteriol

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Partial reversion mutants derived from a strain containing a strongly polar initiator-defective mutation (aracl036).in the L-arabinose operon were found to have several characteristics expected ofmutants with reduced initiator function. These reversion mutations are cotransduced with the ara region and are probably within the aral region. Furthermore, they permit induction of the irarabinose operon to a level only one-third of the normal wild-type level. These partially functional initiator regions reduce the expression ofstructural genes in the cis position only; they function quite independently of wild-type or defective initiator regions in the trans position. These mutants exhibit a two-to threefold increase in the rate of expression of ara operon genes within one-tenth of a generation after a shift ofthe growth temperature from 28 to 420C. This suggests that the temperature optimum for initiation of operon expression is higher for the partial revertant strains than it is for strains containing a wild-type initiator region.

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Construction of pBR322-ara hybrid plasmids by in vivo recombination

et al. 1980

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In vivo recombination was used to clone deletions of the araBAD-araC genes of Escherichia coli onto a hybrid pBR322-ara plasmid. Genetic and physical analyses demonstrated that the desired deletions had been recombined onto the plasmid. In addition to permitting a detailed physical analysis of various ara deletions, this procedure has generated a series of plasmid cloning vehicles that can be used to clone, by in vivo recombination, any ara point mutation located within the region covered by the deletions. Hybrid plasmids containing the cloned point mutation can be distinguished from the original cloning vehicle by genetic complementation. The desired recombinant plasmid can be easily obtained because the frequency of recombination between the plasmid ara region and the chromosomal ara region is 0.025%--3%. A plasmid containing a deletion which removes the ara controlling site region and the araC gene was used to clone two types of araBAD promoter mutations and an araC mutation by in vivo recombination. Genetic and physical analysis of these plasmids established that the mutations in question had been recombined on to the ara deletion plasmid. The application of this procedure to the ara genes and to other genetic systems is discussed.

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Characterization of Strong Polar Mutations in a Region Immediately Adjacent to the l -Arabinose Operator in Escherichia coli B/r

Cited by 9 publications

References 35 publications

Mutations in the l -Arabinose Operon of Escherichia coli B/r That Result in Hypersensitivity to Catabolite Repression

Mutations in the l -Arabinose Operon of Escherichia coli B/r That Result in Hypersensitivity to Catabolite Repression

Mutations in the L-arabinose operon of Escherichia coli B/r with reduced initiator function

Construction of pBR322-ara hybrid plasmids by in vivo recombination

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