Identification, transcriptional and phylogenetic analysis of the DNA polymerase gene of Pieris rapae granulovirus.

Abstract  The DNA polymerase gene (dnapol) of thePieris rapaegranulovirus (PiraGV) was completely sequenced and located between 73.1 and 76 m.u. on the PiraGV genome. Its open reading frame (ORF) has 3135 nucleotides (35% G-C content) encoding 1045 amino acids with a predicted molecular mass of 122.16 kDa. Homology analysis indicated that PiraGVdnapolhad 28–66% amino acid identity to that of other known baculoviruses. Comparative sequence analyses demonstrated that the PiraGVdnapolgene contains conserved 3′–5′ exonuclease motifs and DNA binding functional domains of the DNA polymerase enzyme found in all known baculovirusdnapols. Northern blot results showed that in infectedPieris rapaelarvae the PiraGVdnapolgene was transcribed as a predominant 3.7 kb mRNA. 5′ and 3′ RACE indicated that the PiraGVdnapoltranscript was initiated from the thymine residue located at −378 nt upstream from the ATG start codon and terminated at the polyadenylation signal AATAAA. Phylogenetic analysis ofdnapolsequences suggests that the PiraGVdnapolis more closely related to that ofCydia pomonellaGV andCryptophlebia leucotretaGV than to those of other baculoviruses. [ABSTRACT FROM AUTHOR]