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Characterization of host range factor 1 (hrf-1) expression in Lymantria dispar M nucleopolyhedrovirus- and recombinant Autographa californica M nucleopolyhedrovirus-infected IPLB-Ld652Y cells.

We previously identified a gene, host range factor 1 (hrf-1), in Lymantria dispar M nucleopolyhedrovirus (LdMNPV) which promoted Autographa californica M nucleopolyhedrovirus (AcMNPV) replication in a nonpermissive cell line IPLB-Ld652Y (Ld652Y). A recombinant AcMNPV, vAcLdPS, that bore hrf-1 controlled by two synthetic baculovirus late promoters and that replicated in Ld652Y cells was constructed. In this study, we constructed a new recombinant AcMNPV, vAcLdPD, bearing only hrf-1 controlled by its own promoter. vAcLdPD replicated in Ld652Y cells in the same manner as vAcLdPS, confirming that hrf-1 alone was sufficient to promote AcMNPV replication in Ld652Y cells. hrf-1 was transcribed as a delayed early gene in LdMNPV but as an immediate early gene in both recombinant AcMNPVs. Primer extension analysis showed that the initiator sequence TCAGT was used as the transcription start site in both LdMNPV and recombinant AcMNPVs. Additional sequencing revealed several regulatory motifs in the hrf-1 upstream region. hrf-1 transcripts in LdMNPV- and vAcLdPS-infected Ld652Y cells terminated near the polyadenylation signal at the end of hrf-1 ORF while in vAcLdPD, the hrf-1 transcripts terminated at a downstream polyadenylation signal at the end of ORF 603. Using Western blot analysis, we detected HRF-1 expression in both recombinant AcMNPV-infected Ld652Y cells but not in LdMNPV-infected Ld652Y cells.

Animals↗

Comparative study on the susceptibility of cutworms (Lepidoptera: Noctuidae) to Agrotis segetum nucleopolyhedrovirus and Agrotis ipsilon nucleopolyhedrovirus.

The common cutworm (Agrotis segetum) and the black cutworm (Agrotis ipsilon) are serious soil pests of many vegetable and field crops all over the world. We have demonstrated the cross-infectivity of two baculoviruses, A. segetum nucleopolyhedrovirus (AgseNPV) and A. ipsilon nucleopolyhedrovirus (AgipNPV) for these two insect pests. The susceptibility of A. segetum to AgipNPV was confirmed by DNA restriction endonuclease analyses of DNA isolated from virus harvested from infected A. segetum larvae. For an initial comparison of both viruses, partial polyhedrin sequences were amplified by PCR, cloned, and sequenced. Both viruses shared a very similar polyhedrin gene sequence resulting in only three amino acid substitutions. Phylogenetic analyses clearly demonstrated that both viruses belong to NPV group II and are most closely related to a clade consisting of Spodoptera exigua NPV, Spodoptera frugiperda NPV, and Spodoptera littoralis NPV. Since AgipNPV shows high virulence for both cutworm species, it appears to be a suitable candidate as a single biological control agent of A. segetum and A. ipsilon.

Animals↗

Characterization of Mamestra configurata nucleopolyhedrovirus enhancin and its functional analysis via expression in an Autographa californica M nucleopolyhedrovirus recombinant.

Enhancin genes have been identified in a number of baculoviruses and enhancin proteins are characterized by their ability to enhance the oral infectivity of heterologous baculoviruses in various lepidopteran insects. Here, we describe the putative enhancin gene from Mamestra configurata nucleopolyhedrovirus (MacoNPV), only the second NPV in which an enhancin-like ORF has been identified. The putative enhancin gene from MacoNPV has a typical baculovirus late promoter (ATAAG) 15 bp upstream from the ATG codon. The enhancin ORF encodes an 847 amino acid protein with a predicted molecular mass of 98 kDa and contains a conserved zinc-binding domain (HEIAH) common to metalloproteases. The MacoNPV enhancin shows approximately 20 % amino acid identity with other baculovirus enhancins. An Autographa californica M nucleopolyhedrovirus (AcMNPV) recombinant, AcMNPV-enMP2, expressing the MacoNPV enhancin gene under control of its native promoter was developed and characterized. Northern blot analysis showed expression of enhancin from 24 through 72 h post-infection. In 2nd-instar Trichoplusia ni larvae, the LD50 of the AcMNPV-enMP2 recombinant was 2.8 polyhedral inclusion bodies (PIB) per larva, 4.4 times lower than that of AcMNPV E2 wild-type virus (12.4 PIB per larva). At biologically equivalent doses, i.e. LD90, the survival time 50 % (ST50) of AcMNPV-enMP2 recombinant and AcMNPV E2 wild-type viruses were not significantly different.

Amino Acid Sequence↗

The GP64 protein of Autographa californica multiple nucleopolyhedrovirus rescues Helicoverpa armigera nucleopolyhedrovirus transduction in mammalian cells.

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) belonging to the group I nucleopolyhedroviruses (NPVs) and expressing the envelope-fusion glycoprotein GP64 transduces a variety of mammalian cells to express foreign genes under the control of mammalian promoters. In contrast, the group II Helicoverpa armigera single NPV (HaSNPV) encoding a different envelope protein, the F protein, shows no detectable infectivity towards mammalian cells. This limitation was overcome by expressing AcMNPV GP64 in HaSNPV. Although the transduction ratios were lower overall, the range of mammalian cell types transduced by HaSNPV was consistent with those transduced by AcMNPV. These findings indicate that the F protein functions only in insect cells, whereas the GP64 protein works in both insect and mammalian cells.

Animals↗

Lymantria dispar nucleopolyhedrovirus hrf-1 expands the larval host range of Autographa californica nucleopolyhedrovirus.

The gypsy moth (Lymantria dispar) is nonpermissive for Autographa californica nucleopolyhedrovirus (AcNPV) infection. We previously isolated a gene, host range factor 1 (hrf-1), from L. dispar nucleopolyhedrovirus that promotes AcNPV replication in Ld652Y cells, a nonpermissive L. dispar cell line (S. M. Thiem, X. Du, M. E. Quentin, and M. M. Berner, J. Virol. 70:2221-2229, 1996). In the present study, we investigated the ability of hrf-1 to alter the larval host range of AcNPV. Bioassays using recombinant AcNPV bearing hrf-1 were conducted with insect larvae by use of oral infection. AcNPV bearing hrf-1 was infectious for neonate L. dispar larvae, with a 50% lethal concentration of 1.2 x 10(5) polyhedral inclusion bodies/ml of diet, which is similar to that of wild-type AcNPV for permissive hosts. AcNPV can kill neonate L. dispar larvae at high doses, but it does not kill third-instar larvae. However, electron microscopy studies of AcNPV-inoculated third-instar larvae revealed virus replication in the midgut cells. PCR analyses indicated that the virus was AcNPV. These results suggest that the block for AcNPV infection of L. dispar larvae is its inability to spread systematically from primary infection sites in the midgut epithelium and that this barrier is leaky in neonates. hrf-1 allows AcNPV to overcome this barrier. AcNPV recombinants bearing hrf-1 were also significantly more infectious for Helicoverpa zea, a resistant species, suggesting that the blocks for AcNPV infection of L. dispar and H. zea larvae may be similar.

Animals↗

Characterization of the interaction between P143 and LEF-3 from two different baculovirus species: Choristoneura fumiferana nucleopolyhedrovirus LEF-3 can complement Autographa californica nucleopolyhedrovirus LEF-3 in supporting DNA replication.

The baculovirus protein P143 is essential for viral DNA replication in vivo, likely as a DNA helicase. We have demonstrated that another viral protein, LEF-3, first described as a single-stranded DNA binding protein, is required for transporting P143 into the nuclei of insect cells. Both of these proteins, along with several other early viral proteins, are also essential for DNA replication in transient assays. We now describe the identification, nucleotide sequences, and transcription patterns of the Choristoneura fumiferana nucleopolyhedrovirus (CfMNPV) homologues of p143 and lef-3 and demonstrate that CfMNPV LEF-3 is also responsible for P143 localization to the nucleus. We predicted that the interaction between P143 and LEF-3 might be critical for cross-species complementation of DNA replication. Support for this hypothesis was generated by substitution of heterologous P143 and LEF-3 between two different baculovirus species, Autographa californica nucleopolyhedrovirus and CfMNPV, in transient DNA replication assays. The results suggest that the P143-LEF-3 complex is an important baculovirus replication factor.

Animals↗

Characterization of Antheraea pernyi nucleopolyhedrovirus p11 gene, a homologue of Autographa californica nucleopolyhedrovirus orf108.

Antheraea pernyi nucleopolyhedrovirus (ApNPV) p11 gene is 309 bp long, potentially encoding 102 amino acids with a predicted molecular weight of 11.2 kDa. ApNPV p11 gene was cloned into the prokaryotic expression vector pQE-30 and P11 was expressed in E. coli M15. Polyclonal antiserum was made against 6xHis tagged P11 protein expressed in E. coli M15. P11 gene transcription was detected as early as 36 h post-infection (p.i.) in tussah pupa and remain at high level up to 96 h p.i. Structural localization revealed that P11 protein was present in polyhedral inclusion bodies (PIB) dilute alkaline saline (DAS) pellet (P) fractions and occlusion-derived virus (ODV), but not in PIB DAS supernatant (S) fractions and budded virus (BV). These results indicated that P11 was associated with ApNPV structure.

Amino Acid Sequence↗

Early pathogenesis of Autographa californica multiple nucleopolyhedrovirus and Helicoverpa zea single nucleopolyhedrovirus in Heliothis virescens: a comparison of the 'M' and 'S' strategies for establishing fatal infection.

Nucleopolyhedroviruses (NPVs) (Baculoviridae) produce fatal infections in larval lepidopteran insects. NPVs are designated SNPVs or MNPVs based on whether the occlusion-derived virus (ODV) that initiates primary midgut infections contains single (S) or multiple (M) nucleocapsids. The principal consequence of this ODV packaging is that primary target cells infected with the M phenotype receive multiple nucleocapsids, whereas those infected by the S phenotype receive only one. To determine the biological significance of this difference in the initial infection strategy, a comparison of the primary and secondary infection patterns of the recombinants Helicoverpa zea SNPV (HzSNPV-hsp70/lacZ) and Autographa californica MNPV (AcMNPV-hsp70/lacZ) in orally inoculated larvae of Heliothis virescens was carried out. At dosages yielding similar final mortalities ( approximately 85 %), primary midgut infections by HzSNPV-hsp70/lacZ (indicated by lacZ expression) were observed 6 h earlier and in greater numbers than those generated by AcMNPV-hsp70/lacZ. Infection of secondary target cells in the tracheal epidermis, however, occurred at the same time and at the same rate for both NPVs. A 2 h delay was observed between the onset of primary and secondary AcMNPV-hsp70/lacZ infection, supporting the hypothesis that early tracheal infections were initiated by ODV nucleocapsids repackaged as budded virus. In contrast, an 8 h delay was observed with HzSNPV-hsp70/lacZ, suggesting that systemic infections were established only after virus replication in primary targets. Significant numbers of both MNPV- and SNPV-infected primary target cells were sloughed from the midgut beginning as early as 16 h post-infection. Midgut cell sloughing may be an important host-mediated selection pressure influencing the evolution of NPV morphology and gene regulation, shaping, in part, baculovirus infection strategies.

Animals↗

Filamentous actin is required for lepidopteran nucleopolyhedrovirus progeny production.

Autographa californica M nucleopolyhedrovirus (AcMNPV) is the prototypical member of the NUCLEOPOLYHEDROSIS: genus of the BACULOVIRIDAE:, a family of large, double-stranded DNA viruses that are highly diverse. Nucleocapsid morphogenesis of AcMNPV and others in the NUCLEOPOLYHEDROVIRUS: genus takes place within the nuclei of infected host cells. Previously, we showed that filamentous actin (F-actin) is essential for this process to occur in AcMNPV-infected cells, an unprecedented finding for a DNA virus that replicates within the nucleus. Because of the fundamental importance of this requirement to our understanding of virus-host interactions, and because of the diversity of viruses included within the Nucleopolyhedrovirus genus, we were compelled to determine whether the replication of other nucleopolyhedroviruses was also F-actin dependent. We report here that progeny virus production of six other lepidopteran nucleopolyhedroviruses, representing both phylogenetic groups I and II within the genus, is also F-actin dependent. The six viruses studied (Spodoptera frugiperda MNPV, Bombyx mori NPV, Orgyia pseudotsugata MNPV, Lymantria dispar MNPV, Anticarsia gemmatalis MNPV and Helicoverpa zea SNPV) were unable to produce progeny in the presence of either cytochalasin D or latrunculin A, two actin-binding agents that interfere with F-actin-dependent processes but differ in their modes of action. F-actin-dependent progeny morphogenesis, therefore, appears to be a characteristic common among viruses in this genus that have lepidopteran hosts.

Actins↗

Importance of virus-medium interactions on the biological activity of wild-type Heliothine nucleopolyhedroviruses propagated via suspension insect cell cultures.

In vitro serial passaging of nucleopolyhedroviruses often results in virus instability, leading to reduction of both yield and biological activity of polyhedra (virus occlusion bodies). In this study, uncloned Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) and cloned Helicoverpa zea single-nucleocapsid nucleopolyhedrovirus (HzSNPV) were each serially passaged five times in both low cost (VPM) and commercial (Excell 401) media using H. zea cell cultures. When the experimental data was analysed as a 2(3) full factorial design (testing two levels of virus, medium and passage number), the passage number was shown to have the most significant effect on polyhedra yield, while the virus-medium interaction had the most important effect on polyhedra biological activity. This interaction was most pronounced for HzSNPV, which experienced a dramatic decline in biological activity when switched from its original Excell 401 medium to the in-house VPM medium. This suggests that genetically homogeneous viruses are less able to adapt to perturbations in the nutrient environment, hence medium changes should be avoided. Therefore, it is important to standardise the scale-up process of nucleopolyhedrovirus biopesticides at the earliest stage of development, especially when it requires both a low cost medium and a plaque purified virus.

Animals↗

A physical map of the Mamestra configurata nucleopolyhedrovirus genome and sequence analysis of the polyhedrin gene.

The genome structure of a nucleopolyhedrovirus (NPV) isolated from the bertha armyworm, Mamestra configurata Walker (Lepidoptera: Noctuidae) (MacoNPV) was analysed with six restriction endonucleases (REN): BamHI, EcoRI, HindIII, PstI, SmaI and Xhol. More than 70 MacoNPV REN fragments were cloned into plasmids pUC18 and pBluescript SK(+). The physical map with 112 restriction sites for the above REN was constructed using double digests and Southern blot hybridization analysis of the MacoNPV DNA clones. The size of the DNA genome of the MacoNPV-90/2 isolate used for this study was estimated at 156 kbp based on REN fragment sizes. The position of the polyhedrin gene, which has by convention been used as the zero point of the REN maps of NPV, was determined by hybridizing the Autographa californica multicapsid nucleopolyhedrovirus HindIII-V fragment clone, which contains most of the polyhedrin gene, with genomic blots of MacoNPV. The cloned MacoNPV fragments identified as containing the polyhedrin gene were sequenced and an ORF coding for a 246 amino acid polypeptide with 98.7% sequence identity with Panolis flammea nucleopolyhedrovirus (PaflNPV) polyhedrin protein was identified. The putative polyhedrin gene sequence had 97.2% and 91.2% identity with the PaflNPV and Mamestra brassicae multicapsid nucleopolyhedrovirus polyhedrin gene sequences, respectively, and also contained an upstream region identical to the highly conserved 12 bp consensus sequence TGTAAGT-AATTT typical of NPV very late genes.

Amino Acid Sequence↗

Distinct gene arrangement in the Buzura suppressaria single-nucleocapsid nucleopolyhedrovirus genome.

The genome organization of the Buzura suppressaria single-nucleocapsid nucleopolyhedrovirus (BusuNPV) was largely elucidated and compared to those of other baculoviruses. A detailed physical map was constructed for the restriction enzymes BamHI, BglI, BglII, EcoRI, HindIII, KpnI, PstI, XbaI and XhoI. The 120.9 kbp viral genome was cloned as restriction fragments into a plasmid library from which about 43.5 kbp of dispersed sequence information was generated. Fifty-two putative open reading frames homologous to those of other baculoviruses were identified and their location in the genome of BusuNPV was determined. Although the gene content of BusuNPV is similar to that of Autographa californica multiple-nucleocapsid nucleopolyhedrovirus, Bombyx mori nucleopolyhedrovirus and Orgyia pseudotsugata multiple-nucleocapsid nucleopolyhedrovirus, the gene order is, however, significantly different from that observed in the other viruses, which have a high degree of collinearity. A new approach (GeneParityPlot) was developed to represent the differences in gene order among baculoviruses when limited sequence information is available and to take advantage of the high degree of gene conservation. The data obtained show that BusuNPV is a distinct baculovirus species and the analyses suggest that gene distribution along baculovirus genomes may be used as a phylogenetic marker.

Animals↗

Phenotypic and genotypic analysis of Helicoverpa armigera nucleopolyhedrovirus serially passaged in cell culture.

Rapid accumulation of few polyhedra (FP) mutants was detected during serial passaging of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) in cell culture. 100% FP infected cells were observed by passage 6. The specific yield decreased from 178 polyhedra per cell at passage 2 to two polyhedra per cell at passage 6. The polyhedra at passage 6 were not biologically active, with a 28-fold reduction in potency compared to passage 3. Electron microscopy studies revealed that very few polyhedra were produced in an FP infected cell (<10 polyhedra per section) and in most cases these polyhedra contained no virions. A specific failure in the intranuclear nucleocapsid envelopment process in the FP infected cells, leading to the accumulation of naked nucleocapsids, was observed. Genomic restriction endonuclease digestion profiles of budded virus DNA from all passages did not indicate any large DNA insertions or deletions that are often associated with such FP phenotypes for the extensively studied Autographa californica nucleopolyhedrovirus and Galleria mellonella nucleopolyhedrovirus. Within an HaSNPV 25K FP gene homologue, a single base-pair insertion (an adenine residue) within a region of repetitive sequences (seven adenine residues) was identified in one plaque-purified HaSNPV FP mutant. Furthermore, the sequences obtained from individual clones of the 25K FP gene PCR products of a late passage revealed point mutations or single base-pair insertions occurring throughout the gene. The mechanism of FP mutation in HaSNPV is likely similar to that seen for Lymantria dispar nucleopolyhedrovirus, involving point mutations or small insertions/deletions of the 25K FP gene.

Amino Acid Sequence↗

Sequence analysis and organization of the Neodiprion abietis nucleopolyhedrovirus genome.

Of 30 baculovirus genomes that have been sequenced to date, the only nonlepidopteran baculoviruses include the dipteran Culex nigripalpus nucleopolyhedrovirus and two hymenopteran nucleopolyhedroviruses that infect the sawflies Neodiprion lecontei (NeleNPV) and Neodiprion sertifer (NeseNPV). This study provides a complete sequence and genome analysis of the nucleopolyhedrovirus that infects the balsam fir sawfly Neodiprion abietis (Hymenoptera, Symphyta, Diprionidae). The N. abietis nucleopolyhedrovirus (NeabNPV) is 84,264 bp in size, with a G+C content of 33.5%, and contains 93 predicted open reading frames (ORFs). Eleven predicted ORFs are unique to this baculovirus, 10 ORFs have a putative sequence homologue in the NeleNPV genome but not the NeseNPV genome, and 1 ORF (neab53) has a putative sequence homologue in the NeseNPV genome but not the NeleNPV genome. Specific repeat sequences are coincident with major genome rearrangements that distinguish NeabNPV and NeleNPV. Genes associated with these repeat regions encode a common amino acid motif, suggesting that they are a family of repeated contiguous gene clusters. Lepidopteran baculoviruses, similarly, have a family of repeated genes called the bro gene family. However, there is no significant sequence similarity between the NeabNPV and bro genes. Homologues of early-expressed genes such as ie-1 and lef-3 were absent in NeabNPV, as they are in the previously sequenced hymenopteran baculoviruses. Analyses of ORF upstream sequences identified potential temporally distinct genes on the basis of putative promoter elements.

Amino Acid Motifs↗

Sequence and organization of the Neodiprion lecontei nucleopolyhedrovirus genome.

All fully sequenced baculovirus genomes, with the exception of the dipteran Culex nigripalpus nucleopolyhedrovirus (CuniNPV), have previously been from Lepidoptera. This study reports the sequencing and characterization of a hymenopteran baculovirus, Neodiprion lecontei nucleopolyhedrovirus (NeleNPV), from the redheaded pine sawfly. NeleNPV has the smallest genome so far published (81,755 bp) and has a GC content of only 33.3%. It contains 89 potential open reading frames, 43 with baculovirus homologues, 6 identified by conserved domains, and 1 with homology to a densovirus structural protein. Average amino acid identity of homologues ranged from 19.7% with CuniNPV to 24.9% with Spodoptera exigua nucleopolyhedrovirus. The conserved set of baculovirus genes has dropped to 29, since NeleNPV lacks an F protein homologue (ac23/ld130). NeleNPV contains 12 conserved lepidopteran baculovirus genes, including that for DNA binding protein, late expression factor 11 (lef-11), polyhedrin, occlusion derived virus envelope protein-18 (odv-e18), p40, and p45, but lacks 21 others, including lef-3, me53, immediate early gene-1, lef-6, pp31, odv-e66, few polyhedra 25k, odv-e25, protein kinase-1, fibroblast growth factor, and ubiquitin. The lack of identified baculovirus homologues may be due to difficulties in identification, differences in host-virus interactions, or other genes performing similar functions. Gene parity plots showed limited colinearity of NeleNPV with other baculoviruses, and phylogenetic analysis indicates that NeleNPV may have existed before the lepidopteran nucleopolyhedrovirus and granulovirus divergence. The creation of two new Baculoviridae genera to fit hymenopteran and dipteran baculoviruses may be necessary.

Animals↗

Sequence analysis of the Spodoptera litura multicapsid nucleopolyhedrovirus genome.

The complete Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) genome contained 139,342 bp with a G+C content of 42.7%, and 141 putative open reading frames (ORFs) or genes of 150 nucleotides or greater that showed minimal overlap. Ninety-six ORFs had homologues in Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), 16 had homologues in other baculoviruses, and 29 were unique to SpltMNPV. The homologues of ubiquitin and gp37 are fused in SpltMNPV. The genome lacked a homologue of the major budded virus glycoprotein gene gp64, but it contained a homologue of ORF130 of Lymantria dispar multicapsid nucleopolyhedrovirus (LdMNPV). There were two homologues of AcMNPV ORF2 (bro gene), and a DnaJ protein gene (SpltORF39) in which the N-terminus showed homologies with the J domain of DnaJ family proteins. Seventeen homologous regions (hrs) were identified, each containing 2-29 palindromic repeats, with an average length of 534 bp and base content (G+C%) of 33.0.

Amino Acid Sequence↗

Identification, expression and phylogenetic analysis of the Anticarsia gemmatalis multicapsid nucleopolyhedrovirus (AgMNPV) Helicase gene.

The helicase gene from Anticarsia gemmatalis multicapsid nucleopolyhedrovirus (AgMNPV) was identified and localized in the 58.85-65.90 m.u. of the viral genomic map. This gene encodes a putative polypeptide of 1221 amino acids containing motifs homologous to those found in the helicase superfamily. Expression of the AgMNPV helicase was observed as early as 4h post-infection (p.i.) up until 10 h p.i. A unique early transcription initiation site was observed upstream a putative TATA box. Phylogenetic analysis of the helicase genes of 23 baculoviruses indicated that the AgMNPV helicase is closely related to the helicase genes from Epiphyas postvitanna multicapsid nucleopolyhedrovirus and Choristoneura fumiferana defective nucleopolyhedrovirus.

Amino Acid Motifs↗

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

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.

Amino Acid Sequence↗