The structure and expression of the mercury-resistance transposon Tn501

The nucleotide sequence of the mercury-resistance transposon Tn501 has been determined and the functional regions have been identified by a variety of techniques. The transposition gene products are structurally and functionally homologous to those of other transposons in the Tn3 family and of other recombination systems. The expression of the transposition genes may be regulated coordinately with that of the mercury-resistance genes. Comparison of related transposons suggests mechanisms for their evolution.