The Tn3-family of Replicative Transposons

The ampicillin-resistance transposon Tn3 is the archetype (“Tn3” being synonymous with “Tn1” or “Tn2”) of a large and widespread family of transposons with representatives in nearly all bacterial phyla including proteobacteria, firmicutes, and cyanobacteria. Family members are modular platforms allowing assembly, diversification, and redistribution of an ever-growing arsenal of antimicrobial resistance genes, thereby contributing along with other mobile genetic elements, to the emergence of multi-drug resistances at a rate that challenges the development of new treatments. They are also prevalent in horizontal transfer of large catabolic operons, allowing bacteria to metabolize various families of compounds, including industrial xenobiotic pollutants.