Molecular Evidence for Distinct Genotypes of Monkey B Virus (Herpesvirus Simiae) Which Are Related to the Macaque Host Species

Although monkey B virus (herpesvirus simiae; BV) is common in all macaque species, fatal human infections appear to be associated with exposure to rhesus macaques (Macaca mulatta), suggesting that BV isolates from rhesus monkeys may be more lethal to nonmacaques than are BV strains indigenous to other macaque species. To determine if significant differences that would support this supposition exist among BV isolates, we compared multiple BV strains isolated from rhesus, cynomolgus, pigtail, and Japanese macaques. Antigenic analyses indicated that while the isolates were very closely related to one another, there are some antigenic determinants that are specific to BV isolates from different macaque species. Restriction enzyme digest patterns of viral DNA revealed marked similarities between rhesus and Japanese macaque isolates, while pigtail and cynomolgus macaque isolates had distinctive cleavage patterns. To further compare genetic diversity among BV isolates, DNA sequences from two regions of the viral genome containing genes that are conserved (UL27 and US6) and variable (US4 and US5) among primate alphaherpesviruses, as well as from two noncoding intergenic regions, were determined. From these sequence data and a phylogenetic analysis of them it was evident that while all isolates were closely related strains of BV, there were three distinct genotypes. The three BV genotypes were directly related to the macaque species of origin and were composed of (i) isolates from rhesus and Japanese macaques, (ii) cynomolgus monkey isolates, and (iii) isolates from pigtail macaques. This study demonstrates the existence of different BV genotypes which are related to the macaque host species and thus provides a molecular basis for the possible existence of BV isolates which vary in their levels of pathogenicity for nonmacaque species.     

The Autographa californica M nucleopolyhedrovirus ac79 gene encodes an early gene product with structural similarities to UvrC and intron-encoded endonucleases that is required for efficient budded virus production

The Autographa californica M nucleopolyhedrovirus (AcMNPV) orf79 (ac79) gene is a conserved gene in baculoviruses and shares homology with genes in ascoviruses, iridoviruses, and several bacteria. Ac79 has a conserved motif and structural similarities to UvrC and intron-encoded endonucleases. Ac79 is produced at early times during infection and concentrates in the nucleus of infected cells at late times, suggesting a cellular compartment-specific function. To investigate its function, an ac79-knockout bacmid was generated through homologous recombination in Escherichia coli. Titration assays showed that budded virus (BV) production was reduced in the ac79-knockout virus compared to control viruses, following either virus infection or the transfection of bacmid DNA. The ac79-knockout virus-infected cells produced plaques smaller than those infected with control ac79-carrying viruses. No obvious differences were observed in viral DNA synthesis, viral protein accumulation, or the formation of occlusion bodies in ac79-knockout and control viral DNA-transfected cells, indicating progression into the late and very late phases of viral infection. However, comparative analyses of the amounts of BV genomic DNA and structural proteins in a given quantity of infectious virions suggested that the ac79-knockout virus produced more noninfectious BV in infected cells than the control virus. The structure of the ac79-knockout BV determined by transmission electron microscopy appeared to be similar to that of the control virus, although aberrant capsid protein-containing tubular structures were observed in the nuclei of ac79-knockout virus-infected cells. Tubular structures were not observed for ac79 viruses with mutations in conserved endonuclease residues. These results indicate that Ac79 is required for efficient BV production.     

Kinetic exclusion assay of monoclonal antibody affinity to the membrane protein Roundabout 1 displayed on baculovirus

The reliable assessment of monoclonal antibody (mAb) affinity against membrane proteins in vivo is a major issue in the development of cancer therapeutics. We describe here a simple and highly sensitive method for the evaluation of mAbs against membrane proteins by means of a kinetic exclusion assay (KinExA) in combination with our previously developed membrane protein display system using budded baculovirus (BV). In our BV display system, the membrane proteins are displayed on the viral surface in their native form. The BVs on which the liver cancer antigen Roundabout 1 (Robo1) was displayed were adsorbed onto magnetic beads without fixative (BV beads). The dissociation constant (K_d, ∼10⁻¹¹ M) that was measured on the Robo1 expressed BV beads correlated well with the value from a whole cell assay (the coefficient of determination, R² = 0.998) but not with the value for the soluble extracellular domains of Robo1 (R² = 0.834). These results suggest that the BV–KinExA method described here provides a suitably accurate K_d evaluation of mAbs against proteins on the cell surface.     

Bean dwarf mosaic virus BV1 protein is a determinant of the hypersensitive response and avirulence in Phaseolus vulgaris

The capacities of the begomoviruses Bean dwarf mosaic virus (BDMV) and Bean golden yellow mosaic virus (BGYMV) to differeBean dwarf mosaic viru certain common bean (Phaseolus vulgaris) cultivars were used to identify viral determinants of the hypersensitive response (HR) and avirulence (avr) in BDMV. A series of hybrid DNA-B components, containing BDMV and BGYMV sequences, was constructed and coinoculated with BDMV DNA-A (BDMV-A) or BDMVA-green florescent protein into seedlings of cv. Topcrop (susceptible to BDMV and BGYMV) and the BDMV-resistant cvs. Othello and Black Turtle Soup T-39 (BTS). The BDMV avr determinant, in bean hypocotyl tissue, was mapped to the BDMV BV1 open reading frame and, most likely, to the BV1 protein. The BV1 also was identified as the determinant of the HR in Othello. However, the HR was not required for resistance in Othello nor was it associated with BDMV resistance in BTS. BDMV BV1, a nuclear shuttle protein that mediates viral DNA export from the nucleus, represents a new class of viral avr determinant. These results are discussed in terms of the relationship between the HR and resistance.     

猴 B 病毒血清学和 PCR 检测结果比较

目的：比较猴B病毒血清抗体和病毒PCR检测结果,阐明动物感染后病毒在机体内的存在状况。方法：采集成年猴血清和三叉神经组织,首先通过ELISA方法检测血清中B病毒抗体,然后采用B病毒舡和徊基因引物通过PCR方法扩增血清DNA和三叉神经组织DNA,比较2种方法的检测结果,并对扩增产物进行序列分析。结果：22份猴血清中,B病毒抗体呈阳性的有13份（59．1％）;PCR结果显示,抗体阴性动物及所有血清DNA模板中均无阳性扩增,但在13份抗体阳性动物的三叉神经组织DNA样品中,PCR阳性4份（30．8％）;gL和gD基因扩增条件及产物分析表明,舡基因的GC含量为64．1％,gD为74．2％,且舡的扩增条件和效果明显优于gD。结论：B病毒感染猴后,将在部分动物神经节中建立潜伏,而础基因更适合作为分子鉴定的靶标。     

Transgenic plants expressing geminivirus movement proteins: abnormal phenotypes and delayed infection by Tomato mottle virus in transgenic tomatoes expressing the Bean dwarf mosaic virus BV1 or BC1 proteins

Transgenic tomato plants expressing wild-type or mutated BV1 or BC1 movement proteins from Bean dwarf mosaic virus (BDMV) were generated and examined for phenotypic effects and resistance to Tomato mottle virus (ToMoV). Fewer transgenic plants were recovered with the wild-type or mutated BC1 genes, compared with the wild-type or mutated BV1 genes. Transgenic tomato plants expressing the wild-type or mutated BV1 proteins appeared normal. Interestingly, although BDMV induces only a symptomless infection in tomato (i.e., BDMV is not well adapted to tomato), transgenic tomato plants expressing the BDMV BC1 protein showed a viral disease-like phenotype (i.e., stunted growth, and leaf mottling, curling, and distortion). This suggests that the symptomless phenotype of BDMV in tomato is not due to a host-specific defect in the BC1 protein. One transgenic line expressing the BC1 gene did not show the viral disease-like phenotype. This was associated with a deletion in the 3' region of the gene, which resulted in expression of a truncated BC1 protein. Several R0 plants, expressing either wild-type or mutated BV1 or BC1 proteins, showed a significant delay in ToMoV infection, compared with non-transformed plants. R1 progeny plants also showed a significant delay in ToMoV infection, but this delay was less than that in the R0 parents. These results also demonstrate that expression of viral movement proteins, in transgenic plants, can have deleterious effects on various aspects of plant development.     

Modifications of microfilaments and microtubules induced by two hepatic tumor promoters,phenobarbital and biliverdin in non-transformed and transformed hepatic cell lines

Microfilaments and microtubules are components of the cytoskeleton which could be implicated in neoplastic transformation. We studied the effect of two hepatic tumor promoters, phenobarbital (PB) and biliverdin (BV), on microfilaments and microtubules of non-transformed (Cl₃) and transformed (FV) hepatic epithelial cells. Cl₃ non-transformed cells cultured in the presence of 1 × 10^–6M BV for 48 h showed a loss of F-actin, fragmentation of actin and the appearance of star-like structures in the cytoplasm, as well as loosening of the peripheral bundle of actin, and some ruffling of cell membranes. In Cl₃ cells exposed to 0.2 × 10^–3M PB a similar disappearance of F-actin staining and a very prominent ruffling of cell membrane were observed. BV and PB also produced in these cells modifications of microtubules characterized by a disappearance of centrosome staining in numerous cells, a condensed ring of tubulin around the nucleus and a depolymerized aspect of the microtubular network. All these modifications of microfilaments and microtubules closely resembled those observed in FV transformed cells in the absence of any treatment (Solvent DMSO only). We did not observe an effect of BV and PB on FV cells.The present data demonstrate that the cytoskeleton of non-transformed epithelial liver cells is sensitive to the action of liver tumor promoters suggesting that it might play a role as to yet be defined in the promotion mechanism.Abbreviations PB phenobarbital - BV biliverdin - TPA 12-0-tetradecanoyl-phorbol 13 acetate - GGT gamma-glutamyl-transpeptidase - DMSO dimethylsulfoxyde     

When parasitic wasps hijacked viruses: genomic and functional evolution of polydnaviruses

The Polydnaviridae (PDV), including the Bracovirus (BV) and Ichnovirus genera, originated from the integration of unrelated viruses in the genomes of two parasitoid wasp lineages, in a remarkable example of convergent evolution. Functionally active PDVs represent the most compelling evolutionary success among endogenous viral elements (EVEs). BV evolved from the domestication by braconid wasps of a nudivirus 100 Ma. The nudivirus genome has become an EVE involved in BV particle production but is not encapsidated. Instead, BV genomes have co-opted virulence genes, used by the wasps to control the immunity and development of their hosts. Gene transfers and duplications have shaped BV genomes, now encoding hundreds of genes. Phylogenomic studies suggest that BVs contribute largely to wasp diversification and adaptation to their hosts. A genome evolution model explains how multidirectional wasp adaptation to different host species could have fostered PDV genome extension. Integrative studies linking ecological data on the wasp to genomic analyses should provide new insights into the adaptive role of particular BV genes. Forthcoming genomic advances should also indicate if the associations between endoparasitoid wasps and symbiotic viruses evolved because of their particularly intimate interactions with their hosts, or if similar domesticated EVEs could be uncovered in other parasites.     

Experimental infection of baboons (Papio cynocephalus anubis) with apathogenic and neurovirulent subtypes of herpesvirus papio 2

Cercopithecine herpesvirus 16 (Herpesvirus papio 2; HVP2) is an alpha-herpesvirus of baboons (Papio spp.) that generally causes minimal to inapparent disease in the natural host species. HVP2 is very closely related genetically and antigenically to Cercopithecine herpesvirus 1 (monkey B virus; BV) of macaques, which is well known for its extreme lethality in nonmacaque species including humans. Preliminary evidence suggests that a mouse model of HVP2 would be an excellent tool for studying zoonotic BV infections. Although the pathogenicity of different BV isolates in mice spans the full range of severity from apathogenic to extremely neurovirulent, testing of multiple HVP2 isolates revealed only two distinct phenotypes in mice regardless of route of inoculation: apathogenic (HVP2ap) and highly neurovirulent (HVP2nv). For the HVP2nv mouse model to truly reflect BV infection in both its natural host and the differential pathogenicity of BV in aberrant host species, HVP2nv should not produce severe disease in its natural host. To test this, juvenile baboons were inoculated with doses of 10(6) or 10(4) plaque-forming units of HVP2ap or HVP2nv by using an oral subdermal inoculation route. Parameters followed included the appearance of lesions, shedding of infectious virus, general health, and the immune response to the infection. Regardless of the inoculum dose used, no differences were noted between the two HVP2 subtypes in baboons in any of the parameters measured. These findings further support the use of the HVP2nv mouse system as a model to elucidate and study the viral determinants associated with cross-species BV neurovirulence.     

2’,3’-Cyclic Nucleotide 3’-Phosphodiesterases Inhibit Hepatitis B Virus Replication

2’,3’-cyclic nucleotide 3’-phosphodiesterase (CNP) is a member of the interferon-stimulated genes, which includes isoforms CNP1 and CNP2. CNP1 is locally expressed in the myelin sheath but CNP2 is additionally expressed at low levels outside the nervous system. CNPs regulate multiple cellular functions and suppress protein production by association with polyadenylation of mRNA. Polyadenylation of Hepatitis B virus (HBV) RNAs is crucial for HBV replication. Whether CNPs interact with polyadenylation signal of HBV RNAs and interfere HBV replication is unknown. In this study, we evaluated expressions of CNP isoforms in hepatoma cell lines and their effects on HBV replication. We found that CNP2 is moderately expressed and gently responded to interferon treatment in HepG2, but not in Huh7 cells. The CNP1 and CNP2 potently inhibited HBV production by blocking viral proteins synthesis and reducing viral RNAs, respectively. In chronic hepatitis B patients, CNP was expressed in most of HBV-infected hepatocytes of liver specimens. Knockdown of CNP expression moderately improved viral production in the HepG2.2.15 cells treated with IFN-α. In conclusion, CNP might be a mediator of interferon-induced response against HBV.     

杆状病毒SpltMNPV SL136蛋白的功能

先前的研究发现斜纹夜蛾核多角体病毒 (Spodopteralituramulticapsidnucleopolyhedrovirus,SpltMNPV)基因组中Sl136表达产物具有膜融合功能。通过RT PCR检测了该基因的转录时相 ;制备该蛋白质的多克隆抗血清 ,SDS PAGE、Western印迹实验证明SL136蛋白质是芽生型病毒粒子特有的蛋白质。该基因在斜纹夜蛾离体细胞系中表达产物分子量为 86、6 5kD的两条带 ,后者与芽生型病毒粒子中检测到的一条蛋白质带分子量基本一致。另外 ,细胞酶联免疫吸附测定 (cellenzyme linkedimmunosorbantassay ,CELISA)实验证明SL136蛋白可分布于重组病毒Bac Sl136和野生型SpltMNPV分别感染的Hi5、Sl zsu 1细胞表面 ,并进行了定量分析。生物测定结果表明 ,弗林蛋白酶 (furin)抑制剂对于病毒感染力没有明显的影响 ,但是抑制病毒蛋白的糖基化却使病毒的滴度大为下降     

Designing Anti-Influenza Aptamers: Novel Quantitative Structure Activity Relationship Approach Gives Insights into Aptamer – Virus Interaction

This study describes the development of aptamers as a therapy against influenza virus infection. Aptamers are oligonucleotides (like ssDNA or RNA) that are capable of binding to a variety of molecular targets with high affinity and specificity. We have studied the ssDNA aptamer BV02, which was designed to inhibit influenza infection by targeting the hemagglutinin viral protein, a protein that facilitates the first stage of the virus’ infection. While testing other aptamers and during lead optimization, we realized that the dominant characteristics that determine the aptamer’s binding to the influenza virus may not necessarily be sequence-specific, as with other known aptamers, but rather depend on general 2D structural motifs. We adopted QSAR (quantitative structure activity relationship) tool and developed computational algorithm that correlate six calculated structural and physicochemical properties to the aptamers’ binding affinity to the virus. The QSAR study provided us with a predictive tool of the binding potential of an aptamer to the influenza virus. The correlation between the calculated and actual binding was R² = 0.702 for the training set, and R² = 0.66 for the independent test set. Moreover, in the test set the model’s sensitivity was 89%, and the specificity was 87%, in selecting aptamers with enhanced viral binding. The most important properties that positively correlated with the aptamer’s binding were the aptamer length, 2D-loops and repeating sequences of C nucleotides. Based on the structure-activity study, we have managed to produce aptamers having viral affinity that was more than 20 times higher than that of the original BV02 aptamer. Further testing of influenza infection in cell culture and animal models yielded aptamers with 10 to 15 times greater anti-viral activity than the BV02 aptamer. Our insights concerning the mechanism of action and the structural and physicochemical properties that govern the interaction with the influenza virus are discussed.     

H7N9感染与神经细胞的血小板活化因子分泌浓度的相关性研究

H7N9病毒感染除引起患者呼吸道症状外,还可能导致中枢神级系统病症。血小板活化因子(Platelet activating factor,PAF)是一种生物活性磷脂,参与神经系统的部分功能。但尚未有研究讨论PAF是否参与H7N9病毒中枢神经系统疾病致病机制。本研究通过H7N9病毒体外感染小鼠小胶质细胞(BV2)和神经母瘤细胞(N2a)发现,H7N9流感病毒可以感染BV2、N2a细胞,引起细胞明显病变并使细胞活性下降;此外H7N9病毒感染BV2细胞后,PAF浓度水平明显上升,PAF乙酰水解酶(Platelet activating factor acetylhydrolase,PAF-AH)基因pafah1b1和pafah2表达水平明显下降。而N2a细胞染毒后PAF-AH基因表达水平明显上升,染毒48h后胞内PAF浓度明显下降。本研究首次将PAF与流感病毒性脑病联系在一起,提示PAF可能参与流感病毒性脑病的致病过程,可作为治疗的药物靶点进行后续研究。     

Proteomic Analysis of Mamestra Brassicae Nucleopolyhedrovirus Progeny Virions from Two Different Hosts

Mamestra brassicae nucleopolyhedrovirus (MabrNPV) has a wide host range replication in more than one insect species. In this study, a sequenced MabrNPV strain, MabrNPV-CTa, was used to perform proteomic analysis of both BVs and ODVs derived from two infected hosts: Helicoverpa armigera and Spodoptera exigua. A total of 82 and 39 viral proteins were identified in ODVs and BVs, respectively. And totally, 23 and 76 host proteins were identified as virion-associated with ODVs and BVs, respectively. The host proteins incorporated into the virus particles were mainly involved in cytoskeleton, signaling, vesicle trafficking, chaperone and metabolic systems. Some host proteins, such as actin, cyclophilin A and heat shock protein 70 would be important for viral replication. Several host proteins involved in immune response were also identified in BV, and a C-type lectin protein was firstly found to be associated with BV and its family members have been demonstrated to be involved in entry process of other viruses. This study facilitated the annotation of baculovirus genome, and would help us to understand baculovirus virion structure. Furthermore, the identification of host proteins associated with virions produced in vivo would facilitate investigations on the involvement of intriguing host proteins in virus replication.     

Baculovirus capsid display potentiates OVA cytotoxic and innate immune responses

Baculoviruses (BV) are DNA viruses that are pathogenic for insects. Although BV infect a range of mammalian cell types, they do not replicate in these cells. Indeed, the potential effects of these insect viruses on the immune responses of mammals are only just beginning to be studied. We show in this paper that a recombinant Autographa californica multiple nuclear polyhedrosis virus carrying a fragment of ovalbumin (OVA) on the VP39 capsid protein (BV-OVA) has the capacity to act as an adjuvant and vector of antigens in mice, thereby promoting specific CD4 and cytotoxic T cell responses against OVA. BV also induced in vivo maturation of dendritic cells and the production of inflammatory cytokines, thus promoting innate and adaptive immune responses. The OVA-specific response induced by BV-OVA was strong enough to reject a challenge with OVA-expressing melanoma cells (MO5 cells) and effectively prolonged survival of MO5 bearing mice. All these findings, together with the absence of pre-existing immunity to BV in humans and the lack of viral gene expression in mammalian cells, make BV a candidate for vaccination.     

Effect of intramuscular baculovirus encoding mutant hypoxia-inducible factor 1-alpha on neovasculogenesis and ischemic muscle protection in rabbits with peripheral arterial disease

Background aimsPeripheral arterial disease (PAD) is a progressive, disabling ailment for which no effective treatment exists. Gene therapy-mediated neovascularization has emerged as a potentially useful strategy. We tested the angiogenic and arteriogenic efficacy and safety of a baculovirus (BV) encoding mutant, oxygen-resistant hypoxia-inducible factor 1-alpha (mHIF-1α), in rabbits with PAD.MethodsAfter assessing the transfection efficiency of the BV.mHIF-1α vector and its tubulogenesis potential in vitro, we randomized rabbits with experimental PAD to receive 1 × 10⁹ copies of BV.mHIF-1α or BV.null (n = 6 per group) 7 days after surgery. Two weeks post-treatment, collateralization (digital angiography) and capillary and arteriolar densities (immunohistochemistry) were measured in the posterior limbs. Ischemic damage was evaluated in adductor and gastrocnemius muscle samples. Tracking of viral DNA in injected zones and remote tissues at different time points was performed in additional rabbits using a BV encoding GFP.ResultsAngiographically visible collaterals were more numerous in BV.mHIF-1α-treated rabbits (8.12 ± 0.42 vs 6.13 ± 1.15 collaterals/cm², P < 0.05). The same occurred with arteriolar (27.9 ± 7.0 vs 15.3 ± 4.0 arterioles/mm²) and capillary (341.8 ± 109.9 vs 208.8 ± 87.7 capillaries/mm², P < 0.05) densities. BV.mHIF-1α-treated rabbits displayed less ischemic muscle damage than BV.null-treated animals. Viral DNA and GFP mRNA were detectable only at 3 and 7 days after injection in hind limbs. Neither the virus nor GFP mRNA was detected in remote tissues.ConclusionsIn rabbits with PAD, BV.mHIF-1α induced neovascularization and reduced ischemic damage, exhibiting a good safety profile at 14 days post-treatment. Complementary studies to evaluate its potential usefulness in the clinic are needed.     

Structure and evolution of a proviral locus of Glyptapanteles indiensis bracovirus

Background

Bracoviruses (BVs), a group of double-stranded DNA viruses with segmented genomes, are mutualistic endosymbionts of parasitoid wasps. Virus particles are replication deficient and are produced only by female wasps from proviral sequences integrated into the wasp genome. Virus particles are injected along with eggs into caterpillar hosts, where viral gene expression facilitates parasitoid survival and therefore perpetuation of proviral DNA. Here we describe a 223 kbp region of Glyptapanteles indiensis genomic DNA which contains a part of the G. indiensis bracovirus (GiBV) proviral genome.

Results

Eighteen of ~24 GiBV viral segment sequences are encoded by 7 non-overlapping sets of BAC clones, revealing that some proviral segment sequences are separated by long stretches of intervening DNA. Two overlapping BACs, which contain a locus of 8 tandemly arrayed proviral segments flanked on either side by ~35 kbp of non-packaged DNA, were sequenced and annotated. Structural and compositional analyses of this cluster revealed it exhibits a G+C and nucleotide composition distinct from the flanking DNA. By analyzing sequence polymorphisms in the 8 GiBV viral segment sequences, we found evidence for widespread selection acting on both protein-coding and non-coding DNA. Comparative analysis of viral and proviral segment sequences revealed a sequence motif involved in the excision of proviral genome segments which is highly conserved in two other bracoviruses.

Conclusion

Contrary to current concepts of bracovirus proviral genome organization our results demonstrate that some but not all GiBV proviral segment sequences exist in a tandem array. Unexpectedly, non-coding DNA in the 8 proviral genome segments which typically occupies ~70% of BV viral genomes is under selection pressure suggesting it serves some function(s). We hypothesize that selection acting on GiBV proviral sequences maintains the genetic island-like nature of the cluster of proviral genome segments described herein. In contrast to large differences in the predicted gene composition of BV genomes, sequences that appear to mediate processes of viral segment formation, such as proviral segment excision and circularization, appear to be highly conserved, supporting the hypothesis of a single origin for BVs.     

The Autographa californica Multiple Nucleopolyhedrovirus ORF78 Is Essential for Budded Virus Production and General Occlusion Body Formation

ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle.     

Identification of BV/ODV-C42, an Autographa californica Nucleopolyhedrovirus orf101-Encoded Structural Protein Detected in Infected-Cell Complexes with ODV-EC27 and p78/83

orf101 is a late gene of Autographa californica nucleopolyhedrovirus (AcMNPV). It encodes a protein of 42 kDa which is a component of the nucleocapsid of budded virus (BV) and occlusion-derived virus (ODV). To reflect this viral localization, the product of orf101 was named BV/ODV-C42 (C42). C42 is predominantly detected within the infected-cell nucleus: at 24 h postinfection (p.i.), it is coincident with the virogenic stroma, but by 72 h p.i., the stroma is minimally labeled while C42 is more uniformly located throughout the nucleus. Yeast two-hybrid screens indicate that C42 is capable of directly interacting with the viral proteins p78/83 (1629K) and ODV-EC27 (orf144). These interactions were confirmed using blue native gels and Western blot analyses. At 28 h p.i., C42 and p78/83 are detected in two complexes: one at approximately 180 kDa and a high-molecular-mass complex (500 to 600 kDa) which also contains EC27.