THE TRANSPOSABLE ELEMENT MARINER CAN EXCISE IN NON-DROSOPHILID INSECTS

Plasmid-based excision assays performed in embryos of two non-drosophi lid species using the mariner transposable element from Drosophila mau ritiana resulted in empty excision sites identical to those observed a fter the excision of mariner from D. mauritiana chromosomes. In the pr esence of the autonomous mariner element Mos1, excision products were recovered from D. melanogaster, D. mauritiana and the blowfly Lucilia cuprina. When a hsp82 heat shock promoter-Mos1 construct was used to s upply mariner transposase, excision products were also recovered from the Queensland fruitfly Bactrocera tryoni. Analysis of DNA sequences a t empty excision sites led us to hypothesise that the mariner excision /repair process involves the formation of a heteroduplex at the excisi on breakpoint. The success of these assays suggests that they will pro vide a valuable tool for assessing the ability of mariner and mariner- like elements to function in non-drosophilid insects and for investiga ting the basic mechanisms of mariner excision and repair.