Hyperactive transposase mutants of the Himar1 mariner transposon

Mariner-family transposable elements are active in a wide variety of organi sms and are becoming increasingly important genetic tools in species lackin g sophisticated genetics, The Himar1 element, isolated from the horn fly, H aematobia irritans, is active in Escherichia coil when expressed appropriat ely. We used this fact to devise a genetic screen for hyperactive mutants o f Hinnar1 transposase that enhance overall transposition from approximate t o 4- to 50-fold as measured in an E. coli assay. Purified mutant transposas es retain their hyperactivity, although to a lesser degree, in an in vitro transposition assay. Mutants like those described herein should enable soph isticated analysis of the biochemistry of mariner transposition and should improve the use of these elements as genetic tools, both in vivo and in vit ro.