Orientation of the tox gene in the prophage of corynebacteriophage beta

Laird, W; Groman, Neal B.

doi:10.1128/jvi.19.1.228-231.1976

Cited by 35 publications

(30 citation statements)

References 9 publications

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“…Second, the location of ctx also differs from those of other phageassociated toxin genes. Those toxin genes are usually located adjacent to the attP site on the phage genomes (Laird and Groman, 1976;Betley and Mekalanos. 1985;Johnson etai, 1986).…”

Section: Discussionmentioning

confidence: 99%

Phage‐conversion of cytotoxin production in Pseudomonas aeruginosa

Hayashi

Baba

Matsui

et al. 1990

Molecular Microbiology

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We isolated a temperate phage which carried the cytotoxin gene (ctx) from a cytotoxin (CTX)-producing Pseudomonas aeruginosa strain, PA158. The phage, phi CTX, had a head with a hexagonal outline and a contractile tail with tail fibres. The phage genome was a linear double-stranded 35.5 kb DNA with single-stranded cohesive ends (cos). The attP, cos and ctx genes were all located very close to one another within a 2.3 kb segment on the phage genome in the order given (in the circular form). phi CTX converted CTX non-producing P. aeruginosa strains into CTX producers. A single copy of phi CTX DNA was integrated at the same site on the host chromosome (attB) in every lysogen, including PA158. However, the amount of CTX produced in these lysogens varied from strain to strain and was less than that in PA158.

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Section: Discussionmentioning

confidence: 99%

Phage‐conversion of cytotoxin production in Pseudomonas aeruginosa

Hayashi

Baba

Matsui

et al. 1990

Molecular Microbiology

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“…Although the genetic evidence strongly suggests that transcription of tox proceeds toward att (16,18), the precise location of att on the vegetative map was not known. Laird and Groman (16) have presented two possible orientations of imm and tox on the prophage map which suggest that the vegetative gene order between h and h' may be either h' imm tox att h or h' imm att tox h. We have recently probed Southern blots ofEcoRI-digested DNA extracted from lysogenic and nonlysogenic C. diphtheriae with 32P-labeled / DNA and have positioned the att site in the approximate 1-kb region between the EcoRI-1-5 and BamHI-4-9 restriction sites (Michel, Rappuoli, Murphy, and Pappenheimer, manuscript in preparation).…”

Section: Discussionmentioning

confidence: 99%

Restriction map of corynebacteriophages beta c and beta vir and physical localization of the diphtheria tox operon

Costa¹,

Michel²,

Rappuoli³

et al. 1981

J Bacteriol

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“…The alleles tox-l, tox-2, tox-30, and tox-45 of the toxin structural gene encode CRMs with molecular weights of 20,000), 26,000, 30,000), and 45,000), respectively (11,29). The orientation of transcription of mRNA from the toxin structural gene is from h toward/i' (11,16). The tox-201 regulatory mutation is expressed in a cisdominant manner with respect to the adjacent toxin structural gene (31).…”

Section: Resultsmentioning

confidence: 99%

“…Previous genetic studies have defined the tox locus of phage /8 (12,15,26), identified the relative positions of several point mutations within the toxin structural gene (11,16), and determined the orientation of transcription of the toxin structural gene (11,16). The present studies were performed to determine the location of the tox-201 regulatory site on the genetic map of phage /3.…”

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confidence: 99%

Regulation of toxinogenesis in Corynebacterium diphtheriae. II. Genetic mapping of a tox regulatory mutation in bacteriophage beta

Welkos¹,

Holmes²

1981

J Virol

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The structural gene for diphtherial toxin is present in corynebacteriophage /8. Previous studies located several point mutations within the tox locus and determined the orientation of transcription of the toxin structural gene. The production of maximal quantities of toxin by Corynebacterium diphtheriae C7(,8) occurs only when the bacteria are iron deficient. Mutations in phage / can affect this control of toxin production by iron. The tox-201 mutation regulates expression of the toxin structural gene in a cis-dominant manner and permits large amounts of toxin to be made under high-iron conditions when phage tox8-21 infects C. diphtheriae C7. In this study tox-201 was found to be closely linked to the structural gene for toxin. We performed a series of multifactor matings to determine the relative positions of tox-201 and several point mutations within the toxin structural gene. The order of these markers on the vegetative genetic map of phage , / was tox-201-tox-4-tox-2-tox-30. These findings establish that the tox-201 regulatory site is closely linked to the end of the toxin structural gene corresponding to the origin of transcription. This location is consistent with our hypothesis that tox-201 defines a cis-dominant regulatory element, such as an operator, promoter, or attenuator, involved in control of toxinogenesis in C. diphtheriae C7(,8). The structural gene for diphtherial toxin is present in the genome of corynebacteriophage /3 (21, 29). Toxin can be produced when phage , is present in Corynebacterium diphtheriae C7 as a prophage, as a vegetatively replicating phage, or as a nonreplicating exogenote in immune lysogenic cells (3, 8). Toxin is not required for growth of phage ,8, and the toxin structural gene is expressed independently of the known essential genes of phage , / (3, 8). Production of toxin by C. diphtheriae is maximal only in medium containing growth-limiting amounts of iron, and toxin production decreases rapidly after excess iron is added (20, 24). The genetic and physiological factors that affect toxinogenesis in C. diphtheriae are reviewed in greater detail in the accompanying paper and elsewhere (3,24,25,31). Mutations in phage , / or in its host, C. diphtheriae C7, can determine increased production of toxin when the mutant C7(/3) lysogens are grown in medium containing excess iron (14, 22, 31). Among the reported phage mutants with this phenotype, /t-ox-1 is most strikingly different from wild-type phage /3 (31). In high-iron medium C7(/30x201) can produce almost 200 times more toxin than C7(/3

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Orientation of the tox gene in the prophage of corynebacteriophage beta

Cited by 35 publications

References 9 publications

Phage‐conversion of cytotoxin production in Pseudomonas aeruginosa

Phage‐conversion of cytotoxin production in Pseudomonas aeruginosa

Restriction map of corynebacteriophages beta c and beta vir and physical localization of the diphtheria tox operon

Regulation of toxinogenesis in Corynebacterium diphtheriae. II. Genetic mapping of a tox regulatory mutation in bacteriophage beta

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