ASSAY FOR MOVEMENT OF LEPIDOPTERAN TRANSPOSON IFP2 IN INSECT CELLS USING A BACULOVIRUS GENOME AS A TARGET DNA

Mutagenesis of baculoviruses by host mobile elements occurs spontaneou sly and frequently during propagation of the viruses in Lepidopteran c ell cultures. Most of the transposons identified as insertions in bacu lovirus genomes are relatively small Class II elements that exhibit a remarkable specificity for TTAA target sites. We have developed a tran sposition assay to analyze the movement of these TTAA-specific Lepidop teran transposons using the baculovirus genome as a target and a lacZ gene under control of the polyhedrin gene promoter as a selective mark er for the transposon. This assay provides the first demonstration tha t a Lepidopteran transposon is capable of transposing while carrying a marker gene in insect cells. The data generated from this assay provi de strong evidence that IFP2 encodes a protein that facilitates its ow n movement. This element may be used in a manner analogous to the P-el ement to mobilize genes in at least some Lepidopteran insect cells. Tr ansposon tagging within the baculovirus genome identified several know n genes and two previously undescribed open reading frames as nonessen tial to in vitro replication of the virus. (C) 1995 Academic Press, In c.