New translocation sequence mediating tetracycline resistance found in Escherichia coli pathogenic for piglets

Identification of additional genes on transposon Tn10: tetC and tetD

Two genes (tetC and tetD) were identified and located on transposon Tn10 between gene tetA and insertion sequence IS10R. Genes tetC and tetD encode proteins of apparent subunit molecular weights of 23,000 and 18,000, respectively. The TetD protein was found to be membrane associated. Tetracycline resistance levels promoted by transposon Tn10 were found to be unaffected in Escherichia coli K-12 when mutants lacking tetC or tetC and tetD were tested. The nucleotide sequence of genes tetC and tetD is reported in the accompanying article (K. Schollmeier and W. Hillen, J. Bacteriol. 160:499-503, 1984).