Nucleotide sequence and phylogenetic analyses of the DNA polymerase gene of Anticarsia gemmatalis nucleopolyhedrovirus

Abstract

The DNA polymerase from Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) was identified and sequenced, and its amino acid sequence was compared with other viral DNA polymerases to identify conserved regions and to reconstruct a phylogenetic tree. The sequence analysis of the AgMNPV DNA polymerase gene revealed the presence of a 2976 nucleotides open reading frame (ORF) encoding a polypeptide of 991 amino acid residues with a predicted molecular mass of 114.7 kDa. Among the baculovirus DNA polymerase genes identified to date, the AgMNPV DNA polymerase gene shared maximum amino acid sequence identity with the DNA polymerase gene of Choristoneura fumiferana nucleopolyhedrovirus defective strain (CfDEFNPV) (94%). The alignment of 140 virus sequences, 23 of them from baculovirus, showed that, of the 10 conserved regions identified, 5 are exclusive to baculoviruses (R1, R5, R9, R6 and R10), only 2 of them (R6 and R10) previously described as such in the literature. Our analysis, based on their positions in the AgMNPV DNA polymerase model, suggests that R9 and R10 could interact with DNA. Phylogenetic analysis of DNA polymerase sequences places the enzyme from AgMNPV within the cluster containing the polymerases of Group I Nucleopolyhedrovirus and suggests that the AgMNPV DNA polymerase is more closely related to that of CfDEFNPV than to those of other baculoviruses.