Expression strategy of densonucleosis virus from Mythimna loreyi

The genome of Mythimna loreyi densovirus (MlDNV) was cloned into the pEMBL(19)+ vector. This clone was infectious upon transfection, both in LD cells and larvae. The genome possessed ITRs of 543 nucleotides of which the distal 126 nucleotides could form a hairpin. The nonstructural (NS) and structural (VP) genes were located on the 5'-halves of the complementary strands and their transcripts started 27 nts downstream of the ITRs. These transcripts had an overlap of 57 nucleotides in middle of the genome. The NS cassette consisted of three genes with NS1 and the overlapping NS2 downstream of NS3. The NS3 gene was spliced out from a fraction of the NS transcripts to allow leaky scanning translation of the downstream bicistronic NS1 and NS2 genes. The four VPs were similarly generated by leaky scanning translation of unspliced mRNA. The 5'-untranslated region of the VP transcript was only seven nucleotides long.