Open AccessThe Toxin-Antitoxin System of the Streptococcal Plasmid pSM19035
Author(s) -
Urszula Zielenkiewicz,
Piotr Cegłowski
Publication year - 2005
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.187.17.6094-6105.2005
Subject(s) - antitoxin , plasmid , operon , biology , microbiology and biotechnology , escherichia coli , bacillus subtilis , streptococcus pyogenes , toxin , bacteria , gene , genetics , staphylococcus aureus
pSM19035 of the pathogenic bacterium Streptococcus pyogenes is a low-copy-number plasmid carrying erythromycin resistance, stably maintained in a broad range of gram-positive bacteria. We show here that the omega-epsilon-zeta operon of this plasmid constitutes a novel proteic plasmid addiction system in which the epsilon and zeta genes encode an antitoxin and toxin, respectively, while omega plays an autoregulatory function. Expression of toxin Zeta is bactericidal for the gram-positive Bacillus subtilis and bacteriostatic for the gram-negative Escherichia coli. The toxic effects of zeta gene expression in both bacterial species are counteracted by proper expression of epsilon. The epsilon-zeta toxin-antitoxin cassette stabilizes plasmids in E. coli less efficiently than in B. subtilis.