Stable transformation of an Anopheles gambiae cell line mediated by the Hermes mobile genetic element

We have used cell transfection techniques to demonstrate that Hermes, a member of the hAT family of transposable genetic elements isolated from the housefly, Musca domestica, is able to transform the genome of the malaria vector mosquito, Anopheles gambiae. Mos55 cells were co-transfected with a Hermes transformation vector and a helper plasmid expressing the hermes transposase. The transformation vector carried a hygromycin resistance marker between the Hermes inverted terminal repeats and was flanked by a negative selection marker (Herpes Simplex Virus - thymidine kinase). Following selection, a number of cell clones were established that had been stably transformed to hygromycin resistance. Analysis of genomic DNA from one such clone revealed four independent copies of the hygromycin resistance transgene. Three of these were shown by Southern analysis to be delimited by the Hermes inverted repeats, having lost all Banking sequences from the transformation vector. A combination of inverse PCR and genomic library screening was used to sequence the junctions between the Her-mes transgenes and the mosquito genome. Sequence data for two left-hand and one right-hand junctions revealed precise boundaries between the Hermes inverted repeats and the flanking genomic DNA, confirming that the integrations had been mediated by transposition. (C) 1998 Elsevier Science Ltd. All rights reserved.