Complete Genomic Sequence of the Amsacta moorei Entomopoxvirus: Analysis and Comparison with Other Poxviruses

Bawden, Alison L; Glassberg, Kathryn J.; Diggans, James; Shaw, Regina; Farmerie, William G.; Moyer, Richard W.

doi:10.1006/viro.2000.0449

Cited by 127 publications

(93 citation statements)

References 94 publications

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“…50 genes (8). Considering that the ancestral virus might have been a simpler entity than its extant descendants, even this conservative reconstruction may be a reasonable approximation of the ancestral set of essential viral genes.…”

Section: Resultsmentioning

confidence: 99%

“…However, viruses belonging to a particular large family, such as the herpesvirus family or the poxvirus family, share between themselves a core set of genes encoding proteins involved in DNA replication, transcription, and virion biogenesis, most of which are only moderately similar to cellular homologs, if such are detectable at all (3,51). The existence of core sets of up to 40 to 50 conserved viral genes (8,22) establishes beyond reasonable doubt that the extant members of the families Herpesviridae and Poxviridae have diverged from the respective ancestral viruses that already possessed the principal features of genome replication and expression and of virion structure that are typical of these viral families. In contrast, it remains unclear whether there are any evolutionary connections between different viral families.…”

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confidence: 99%

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Common Origin of Four Diverse Families of Large Eukaryotic DNA Viruses

Iyer

Aravind

Koonin

2001

J Virol

500

504

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Comparative analysis of the protein sequences encoded in the genomes of three families of large DNA viruses that replicate, completely or partly, in the cytoplasm of eukaryotic cells (poxviruses, asfarviruses, and iridoviruses) and phycodnaviruses that replicate in the nucleus reveals 9 genes that are shared by all of these viruses and 22 more genes that are present in at least three of the four compared viral families. Although orthologous proteins from different viral families typically show weak sequence similarity, because of which some of them have not been identified previously, at least five of the conserved genes appear to be synapomorphies (shared derived characters) that unite these four viral families, to the exclusion of all other known viruses and cellular life forms. Cladistic analysis with the genes shared by at least two viral families as evolutionary characters supports the monophyly of poxviruses, asfarviruses, iridoviruses, and phycodnaviruses. The results of genome comparison allow a tentative reconstruction of the ancestral viral genome and suggest that the common ancestor of all of these viral families was a nucleocytoplasmic virus with an icosahedral capsid, which encoded complex systems for DNA replication and transcription, a redox protein involved in disulfide bond formation in virion membrane proteins, and probably inhibitors of apoptosis. The conservation of the disulfide-oxidoreductase, a major capsid protein, and two virion membrane proteins indicates that the odd-shaped virions of poxviruses have evolved from the more common icosahedral virion seen in asfarviruses, iridoviruses, and phycodnaviruses.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Common Origin of Four Diverse Families of Large Eukaryotic DNA Viruses

Iyer

Aravind

Koonin

2001

J Virol

500

504

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“…Little is known about the 553-aa baculovirus HE65 protein, except that its gene is transcribed at early times during virus infection. A 524-aa Rnl2-like protein is also encoded by the Amsacta moorei entomopoxvirus (AmEPV), a cytoplasmic poxvirus that infects caterpillars (36). It is notable that Rnl2-like putative ligases in the eukaryotic domain are apparently restricted to viruses (baculo and entomopox) and protozoa (Trypanosoma and Leishmania) that spend all or part of their life cycles in an arthropod host.…”

Section: Rnl2 Exemplifies An Rna Ligase Family Found In All Phylogeneticmentioning

confidence: 99%

Bacteriophage T4 RNA ligase 2 (gp24.1) exemplifies a family of RNA ligases found in all phylogenetic domains

Shuman²

2002

Proc. Natl. Acad. Sci. U.S.A.

150

174

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RNA ligases participate in repair, splicing, and editing pathways that either reseal broken RNAs or alter their primary structure. Bacteriophage T4 RNA ligase (gp63) is the best-studied member of this class of enzymes, which includes yeast tRNA ligase and trypanosome RNA-editing ligases. Here, we identified another RNA ligase from the bacterial domain-a second RNA ligase (Rnl2) encoded by phage T4. Purified Rnl2 (gp24.1) catalyzes intramolecular and intermolecular RNA strand joining through ligase-adenylate and RNA-adenylate intermediates. Mutational analysis identifies amino acids required for the ligase-adenylation or phosphodiester synthesis steps of the ligation reaction. The catalytic residues of Rnl2 are located within nucleotidyl transferase motifs I, IV, and V that are conserved in DNA ligases and RNA capping enzymes. Rnl2 has scant amino acid similarity to T4 gp63. Rather, Rnl2 exemplifies a distinct ligase family, defined by variant motifs, that includes the trypanosome-editing ligases and a group of putative RNA ligases encoded by eukaryotic viruses (baculoviruses and an entomopoxvirus) and many species of archaea. These findings have implications for the evolution of covalent nucleotidyl transferases and virus-host dynamics based on RNA restriction and repair.T 4 RNA ligase (1) is the founding member of a family of RNA end-joining enzymes involved in RNA repair, splicing, and editing pathways (2-8). T4 RNA ligase joins 3Ј OH and 5Ј PO 4 RNA termini by means of three nucleotidyl transfer steps similar to those of DNA ligases (9-11).Step 1 is the reaction of RNA ligase with ATP to form a covalent ligase-(lysyl-N)-AMP intermediate. In step 2, the AMP is transferred to a 5Ј PO 4 RNA end to form an RNA-adenylate intermediate (AppRNA). In step 3, attack by an RNA 3Ј OH on RNA-adenylate seals the ends and releases AMP. T4 RNA ligase can join two single-stranded RNA molecules without a complementary bridging polynucleotide. T4 RNA ligase can also catalyze intramolecular ligation to form a covalently closed RNA circle. RNA ligase has been a powerful tool in the synthesis of RNAs of defined sequence, RNA 3Ј end modification, RNA 3Ј end-labeling, RNA sequencing, and structural analysis (11).During T4 infection in vivo, the RNA ligase, together with T4 polynucleotide kinase (Pnk), performs an RNA repair function that remodels and then seals broken tRNA ends. In Escherichia coli strains containing the prr locus, the host cell tRNA Lys is cleaved 5Ј to the wobble position by a T4-induced anticodon nuclease. If Pnk and RNA ligase are not present, the synthesis of viral proteins is blocked by depletion of tRNA Lys , and the phage cannot replicate (2,(12)(13)(14). This pathway represents an RNA-based restriction system of host defense against a foreign invader. tRNA anticodon nuclease systems are present in other pathogenic bacteria (14). The bacterial toxins colicins D and E5 are also anticodon nucleases that attack specific tRNAs (15). Thus, RNA repair enzymology has broad significance as a means to combat, or reco...

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“…Genomic sequencing has identified two candidate iap genes in Melanoplus sanguinipes (Orthoptera) entomopoxvirus (MsEPV), MSV248 and MSV242, and a single iap gene in Amsacta moorei (lepidopteran) entomopoxvirus (AmEPV), AMV021, hereafter termed AMV-iap (1,2). Recent work has established that deletion of the AMV-iap gene results in lowered viral yields, but that the AMV-iap gene is not essential for viral propagation in vitro.…”

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confidence: 99%

Amsacta moorei Entomopoxvirus Inhibitor of Apoptosis Suppresses Cell Death by Binding Grim and Hid

Liston

Schokman

et al. 2005

J Virol

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Inhibitor of apoptosis (iap) genes have been identified in the genomes of two independent families of insect viruses, the Baculoviridae and the Entomopoxvirinae. In this report, we examined the functional attributes of the Amsacta moorei entomopoxvirus-encoded IAP protein (AMV-IAP). The binding specificity of the individual baculoviral IAP repeat (BIR) domains of AMV-IAP was investigated by using a random-peptide, phage display library, and sequences similar to the amino termini of proapoptotic Drosophila proteins in the Reaper/Hid/ Grim family were identified. Furthermore, the BIR domains of AMV-IAP protein were demonstrated to bind the mammalian IAP inhibitor Smac through the AVPI tetrapeptide sequence, suggesting that the peptide binding pocket and groove found in the insect and mammalian IAPs is conserved in this viral protein.Interaction analysis implicated BIR1 as the high-affinity site for Grim, while BIR2 interacted more strongly with Hid. Both Grim and Hid were demonstrated to interact with AMV-IAP in vivo, and Grim-or Hid-induced cell death was suppressed when AMV-IAP was coexpressed.Apoptosis, or programmed cell death, is used as a strategic response to eliminate infected cells and thus limit the replication of viruses within the host. The coevolution of viruses and their hosts has resulted in the development of viral strategies to circumvent this response (3). Multiple unrelated virus families have independently targeted the extrinsic death receptor pathways and the intrinsic mitochondrial pathways. Both extrinsic and intrinsic apoptotic pathways trigger a cascade of caspase activation, which leads ultimately to apoptosis. The extrinsic pathways can be thwarted through the expression of virally encoded soluble death receptors, inducing the down-regulation of cellular death receptors or the blockade of the signal transduction pathway by viral FLICE-like inhibitory proteins. Intrinsic pathway signaling can also be blocked at several points, most frequently involving the expression of functional inhibitors of p53 or of viral homologs of the Bcl-2 family (3).Viruses have also developed strategies to target the caspase cascade constituting the ultimate convergence of the extrinsic and intrinsic apoptotic pathways. Several poxvirus-encoded proteins that regulate apoptosis through inhibition of the caspase cascade have been identified (29). Members of the Poxviridae family infect a wide range of vertebrate and invertebrate species, and are subdivided into the Entomopoxvirinae (insect pathogens) and Chordopoxvirinae (mammalian and avian pathogens). Among the Chordopoxvirinae, cowpox virus encodes a unique serpin (serine protease inhibitor) called the cytokine response modifier A (CrmA, also known as SPI-2). CrmA/SPI-2 is able to inhibit a broad range of initiator caspases, including caspase-1, caspase-8, caspase-4, caspase-5, caspase-9, and caspase-10, in order of decreasing affinity, thus inhibiting apoptosis as well as interfering with the host inflammatory reaction (36).The only definitive virally encoded...

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Complete Genomic Sequence of the Amsacta moorei Entomopoxvirus: Analysis and Comparison with Other Poxviruses

Cited by 127 publications

References 94 publications

Common Origin of Four Diverse Families of Large Eukaryotic DNA Viruses

Common Origin of Four Diverse Families of Large Eukaryotic DNA Viruses

Bacteriophage T4 RNA ligase 2 (gp24.1) exemplifies a family of RNA ligases found in all phylogenetic domains

Amsacta moorei Entomopoxvirus Inhibitor of Apoptosis Suppresses Cell Death by Binding Grim and Hid

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