NUCLEOTIDE-SEQUENCE OF A 5423 BASE-PAIRS FRAGMENT OF THE LSNPV GENOMEAND COMPARISON WITH THE ACNPV GENOME

A 5423 bp fragment of LsNPV genome was sequenced, in which PDV-E66 gen e and another four ORFs were found. The PDV-E66 gene of LsNPV was comp ared with the PDV-E66 gene of AcNPV, and a 51.9% nucleotide sequence h omology and 38.8% amino acid sequence homology were found between the two genes. Two conserved late transcriptional motifs TAAG were found i n LsNPV PDV-E66 gene, similar to those in AcNPV PDV-E66. The LsNPV PDV -E66 ORF is 204 base pairs shorter than the AcNPV PDV-E66 ORF at the 5 ' end. This is agreement with the fact that the N-terminus of the AcNP V PDV-E66 mature protein is 69 amino acids interior to the N-terminus predicted by the AcNPV PDV-E66 ORE The 5' regulatory region of ORF1 co ntains early (CGTGC) and late (TAAG) transcriptional initiation motifs and ORFI is predicted to encode a protein with 114 amino acid residue s. The 5' regulatory region of ORF2 which can encode a protein with 11 5 amino acid residues contains only an early transcriptional initiatio n motif. Compared with all the genes from AcNPV and other baculoviruse s, ORFI and ORF2 have no homologous genes. It is suggested that ORF1 a nd ORF2 may be two novel baculovirus genes. ORF3 (PDV-E66 gene), ORF5 and an incomplete ORE ORF6-part, have homologous regions in the AcNPV genome. ORF3, ORF5, ORF6-part are linked together in LsNPV genome, but their homologous regions are separated by about 58 kb fragment in the AcNPV genome. This fact indicates that the organization of the above genes in LsNPV is different from that of AcNPV. ORF4 is included in OR F6-part and can encode a 48 amino acid residues polypeptide, but ORF4 and ORF6-part are located on different DNA strands.