Germline transformation of Drosophila melanogaster by purified P element transposase.

P transposable elements are used as vectors for germline transformation of Drosophila melanogaster (1-3). P element transposition requires an 87 kD P element-encoded transposase protein (4). The conventional transformation protocol involves microinjection of embryos with a genetically marked, nonautonomous P element along with a second DNA encoding the transposase gene. Transposase synthesized from the second DNA acts in trans to stimulate transposition of the nonautonomous P element into germline chromosomes (1-3). We have purified P element transposase protein (5), and wished to determine if it retained the ability to stimulate P element transposition in vivo