38th Annual Meeting of the Society for Invertebrate Pathology

The genome of ChchNPV, a nucleopolyhedrovirus recently isolated from Chrysodeixis chalcites larvae, has a size of 149,622 base pairs, an overall G+C content of 39.1 % and contains 151 predicted open reading frames (ORFs). Typical baculovirus homologous regions (hrs) were not observed. ChchNPV belongs phylogenetically to group II NPVs, but in contrast to other group II NPVs encodes a proliferating cell nuclear antigen. Twenty-four unique baculovirus genes were identified, including a gene encoding a novel RING finger protein with a possible homologue in poxviruses. Most remarkable is the presence of two ORFs, phr-1 and phr-2, which encode class II cyclobutane pyrimidine dimer (CPD) DNA photolyases, proteins with a predicted role in photo-reactivation of UV damaged DNA. The two phr genes share 45% identity at the amino acid level and have different putative promoter motifs. They form a monophyletic group with photolyases of (entomo-) pox viruses. The presence of a full complement of genes potentially involved in preventing mutagenic incorporations (dUTPase, ld138, rr1 and rr2), as well as two genes (phr-1 and phr-2) with a predicted role in UV damage repair, might play an important role in the ecology of this virus and may indicate that ChchNPV is uniquely protected against mutations.