Open AccessSynthesis of Diphtheria tox -Gene Products in Escherichia coli Extracts
Author(s) -
John R. Murphy,
Alwin M. Pappenheimer,
S. Tayart De Borms
Publication year - 1974
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.71.1.11
Subject(s) - corynebacterium diphtheriae , diphtheria toxin , escherichia coli , dna , toxin , microbiology and biotechnology , strain (injury) , diphtheria , biology , chemistry , gene , biochemistry , virology , vaccination , anatomy
In a protein-synthesizing system extracted fromE. coli , purified DNA from corynephages βctox+ and β45c was used to direct thein vitro synthesis of diphtheria toxin and of the related nontoxic protein, CRM45, as well as of other β-phage proteins. When βctox+ -DNA or βc-DNA was added to a similar system extracted from the nonlysogenicCorynebacterium diphtheriae strain, C7s (-)tox- , neither toxin nor the CRM45 protein was produced, although other β-phage proteins were synthesized in amounts equivalent to those produced in theE. coli system from the same amount of β-phage DNA. Preliminary experiments suggest that both toxinogenic and nontoxinogenic strains of the diphtheria bacillus contain a factor that specificially blocks expression of thetox gene. Synthesis of toxin and the CRM45 protein in theE. coli system could not be inhibited by relatively high concentrations of inorganic iron, but could be inhibited by extracts from the C7s (-)tox- strain ofC. diphtheriae .