Fig. 3: Identification of a type I toxin-antitoxin encoded by the pOXA-48 plasmid.
From: Genetic determinants of pOXA-48 plasmid maintenance and propagation in Escherichia coli
a Tn-Seq data showing read counts for transposon insertions across the agrB/dqlB region of the pOXA-48 plasmid. The schematic below illustrates the genomic organization of the predicted toxin-antitoxin system, with agrB in green encoding the antitoxin (A) and dqlB in gray the toxin (T). b Spot assays evaluating the toxicity of DqlB and the protective effect of agrB. Growth of E. coli (−/−; LY4078), E. coli producing agrB (LY4080), DqlB (LY4079) or agrB and DqlB (LY4081) is shown under conditions with either glucose or arabinose. c Schematic representation of the Targeted Antibacterial Plasmid (TAP) system used to investigate the role of agrB and DqlB. Donor cells carry a TAP-OXA degrading the pOXA-48 plasmid, leading to cell death or a TAP-OXA-A targeting the pOXA-48 plasmid but producing the antitoxin gene to counteract the toxin activity and rescue the transconjugant cell. The histograms show the number of viable transconjugants (CFU/mL) after acquisition of the different TAPs. Donors TAP-nsp (LY1369), TAP-OXA48 (LY1522), TAP-OXA48-PemI (LY1549), TAP-OXA48-agrB (LY4038); Recipients (MS388). Mean and SD are calculated from six independent experiments. P-value significance from Tukey’s multiple comparisons statistical analysis is indicated by ns: not significant, *** (p = 0.0002), **** (p < 0.0001). d Histograms showing the proportion of Inc plasmids containing a dqlB-like homolog.
