Open AccessSynthesis of an R plasmid protein associated with tetracycline resistance is negatively regulated.
Author(s) -
HueyLang Yang,
Geoffrey Zubay,
Stuart B. Levy
Publication year - 1976
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.73.5.1509
Subject(s) - plasmid , tetracycline , escherichia coli , biology , in vitro , protein biosynthesis , microbiology and biotechnology , dna , gene , plasmid preparation , biochemistry , antibiotics , pbr322
Synthesis of proteins encoded by the R222 plasmid was observed in a DNA-directed cell-free system and the products were compared to those plasmid proteins synthesized in Escherichia coli minicells. A greater number of plasmid-specified proteins was detected in the in vitro system than in the minicell, suggesting the presence of control factors for plasmid gene expression in the minicell. Synthesis of a newly detected plasmid protein (TET protein) is induced by tetracycline in minicells containing tetracycline-resistant plasmids, including R222, and this induced synthesis correlates with induced host resistance to the drug. This TET protein was synthesized in vitro from R222 DNA in the absence of tetracycline, indicating that no positive regulatory role for tetracycline is required for the protein's synthesis. TET proteon synthesis was inhibited in vitro when cell-free extracts prepared from cells containing the R222 plasmid were used.