The Integration Machinery of ZAM, a Retroelement from Drosophila melanogaster, Acts as a Sequence-Specific Endonuclease

Retroviruses and retrotransposons insert into the host genome with no obvious sequence specificity. We examined the target sites of the retroelement ZAM by sequencing each host-ZAM junction in the genome of Drosophila melanogaster. Our overall data provide compelling evidence that ZAM integration machinery recognizes and leads to ZAM insertion into the sequence 5′-GCGCGCg-3′. This unique property of ZAM will facilitate the development of new tools to study the integration process of retroelements.