Host-dependent transposition of Tn5041

A study was made of the transposition of the mercury resistance transposon Tn5041 which, together with the closely related toluene degradation transpo son Tn4651, forms a separate group in the Tn3 family. Transposition of Tn50 41 was host-dependent: the element transposed in its original host Pseudomo nas sp. KHP41 but not in P. aeruginosa PAO-R and Escherichia coli K12. Tran sposition of Tn5041 in these strains proved to be complemented by the trans posase gene (tnpA) of Tn4651. The gene region determining the host dependen ce of the Tn5041 transposition was localized with the use of a series of hy brid (Tn5041 x Tn4651) tnpA genes. Its location in the 5'-terminal one-thir d of the transposase gene is consistent with the data that this region is i nvolved in the formation of the transposition complex in transposons of the Tn3 family. As in other transposons of this family, transposition of Tn504 1 occurred via cointegrate formation, suggesting its replicative mechanism. However, neither of the putative resolution proteins encoded by Tn5041 res olved the cointegrates formed during transposition or an artificial cointeg rate in E. coli K12. Similar data were obtained with the mercury resistance transposons isolated from environmental Pseudomonas strains and closely re lated to Tn5041 (Tn5041 subgroup).