Sequence and analysis of the genome of a Baculovirus pathogenic for Lymantria dispar

The genome of the Lymantria dispar multinucleocapsid nucleopolyhedrovirus ( LdMNPV) was sequenced and analyzed. It is composed of 161,046 bases with a G + C content of 57.5% and contains 163 putative open reading frames (ORFs) of greater than or equal to 150 nucleotides. Homologs were found to 95 of the 155 genes predicted for the Autographa californica MNPV (AcMNPV) genome . More than 9% of the LdMNPV genome was occupied by 16 repeated genes relat ed to AcMNPV ORF2. Readily identifiable homologs of several genes that have been reported to play important roles in the AcMNPV life cycle are not pre sent; these include ie-2, a transcriptional transactivator, and gp64, a maj or envelope glycoprotein of the nonoccluded form of the virus. A number of genes lacking in AcMNPV but present in other baculoviruses were identified; these include two viral enhancing factor homologs, a second copy of a cono toxin-like gene, and a dutpase homolog. Although a single gene predicted to encode a large subunit of ribonucleotide reductase was found, two differen t copies of the small subunit gene were present. In addition, homologs of g enes not previously reported for baculoviruses were identified, including a predicted protein with homology to DNA ligases and another that has motifs most closely related to a yeast mitochondrial helicase. Thirteen homologou s regions (hrs) containing 54 repeated sequences that include 30-bp imperfe ct palindromes were identified. The imperfect palindromes are related to th ose from other baculoviruses. (C) 1999 Academic Press.