IDENTIFICATION AND SEQUENCE-ANALYSIS OF THE INTEGRATION SITE OF TRANSPOSON TCP3.2 IN THE GENOME OF CYDIA-POMONELLA GRANULOVIRUS

Recently, we described the isolation and characterisation of the novel lepidopteran transposon TCp3.2, which was found to be inserted into t he genome of a spontaneous mutant of the baculovirus Cydia pomonella g ranulovirus (CpGV). Transposon TCp3.2, which is a member of the Tcl/ma riner superfamily, is an apparently defective copy which became stably integrated into the viral genome (Jehle et al., 1997. J. Mol. Evol., in press). In this study, we located, cloned and sequenced a genomic r egion of 2.5 kb of CpGV which encompasses the insertion site of TCp3.2 . The TCp3.2 was inserted at a TA dinucleotide as it is typical for ma ny Tcl/mariner-like transposons. The TA insertion site was localised w ithin a non-translated region downstream of the homologous gene of bac ulovirus late expression factor 2 (lef-2). Additionally, three other c omplete open reading frames (ORF35Ra, ORF35Rb, and ORF36L) with unknow n functions were identified. Transposon insertion into intergenic regi ons of viral genomes may contribute to the genotypic variability of ba culoviruses without any phenotypic effect. (C) 1997 Elsevier Science B .V.