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Unique and conserved features of genome and proteome of SARS-coronavirus, an early split-off from the coronavirus group 2 lineage
, 2003
"... *Corresponding authors The genome organization and expression strategy of the newly identified severe acute respiratory syndrome coronavirus (SARS-CoV) were predicted using recently published genome sequences. Fourteen putative open reading frames were identified, 12 of which were predicted to be ex ..."
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Cited by 146 (25 self)
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*Corresponding authors The genome organization and expression strategy of the newly identified severe acute respiratory syndrome coronavirus (SARS-CoV) were predicted using recently published genome sequences. Fourteen putative open reading frames were identified, 12 of which were predicted to be expressed from a nested set of eight subgenomic mRNAs. The synthesis of these mRNAs in SARS-CoV-infected cells was confirmed experimentally. The 4382- and 7073 amino acid residue SARS-CoV replicase polyproteins are predicted to be cleaved into 16 subunits by two viral proteinases (bringing the total number of SARS-CoV proteins to 28). A phylogenetic analysis of the replicase gene, using a distantly related torovirus as an outgroup, demonstrated that, despite a number of unique features, SARS-CoV is most closely related to group 2 coronaviruses. Distant homologs of cellular RNA processing enzymes were identified in group 2 coronaviruses, with four of them being conserved in SARS-CoV. These newly recognized viral enzymes place the mechanism of coronavirus RNA synthesis in a completely new perspective. Furthermore, together with previously described viral enzymes, they will be important targets for the design of antiviral strategies aimed at controlling the further spread of SARS-CoV.
Coronavirus M proteins accumulate in the Golgi complex beyond the site of virion budding
- J
, 1994
"... The prevailing hypothesis is that the intracellular site of budding of coronaviruses is determined by the localization of its membrane protein M (previously called El). We tested this by analyzing the site of budding of four different coronaviruses in relation to the intracellular localization of th ..."
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Cited by 51 (6 self)
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The prevailing hypothesis is that the intracellular site of budding of coronaviruses is determined by the localization of its membrane protein M (previously called El). We tested this by analyzing the site of budding of four different coronaviruses in relation to the intracellular localization of theirM proteins. Mouse hepatitis virus (MHV) and infectious bronchitis virus (IBV) grown in Sac(-) cells, and feline infectious peritonitis virus (FIPV) and transmissible gastroenteritis virus (TGEV) grown in CrFK cells, all budded exclusively into smooth-walled, tubulovesicular membranes located intermediately between the rough endoplasmic reticulum and Golgi complex, identical to the so-called budding compartment previously identified for MHV. Indirect immunofluorescence staining of the infected cells showed that all fourM proteins accumulated in a perinuclear region. Immunogold microscopy localized MHV M and IBV M in the budding compartment; in addition, a dense labeling in the Golgi complex occurred, MHV M predominantly in trans-Golgi cisternae and trans-Golgi reticulum and IBV M mainly in the cis and medial Golgi cisternae. The corresponding M proteins of the four viruses, when independently expressed in a recombinant vaccinia virus system, also accumulated in the perinuclear area. Quantitative pulse-chase analysis of metabolically labeled cells showed that in each case the majority of the M glycoproteins carried oligosaccharide side chains with Golgi-specific modifications within 4 h after synthesis. Immunoelectron microscopy localized recombinant MHV M and IBV M to the same
The genome organization of the Nidovirales: similarities and differences between arteri-, toro-, and coronaviruses
- Semin Virol
, 1997
"... Viruses in the families Arteriviridae and Coronaviridae have enveloped virions which contain nonseg-mented, positive-stranded RNA, but the constituent genera differ markedly in genetic complexity and virion structure. Nevertheless, there are striking resemblances among the viruses in the organizatio ..."
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Cited by 49 (11 self)
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Viruses in the families Arteriviridae and Coronaviridae have enveloped virions which contain nonseg-mented, positive-stranded RNA, but the constituent genera differ markedly in genetic complexity and virion structure. Nevertheless, there are striking resemblances among the viruses in the organization and expression of their genomes, and sequence conservation among the polymerase polyproteins strongly suggests that they have a common ancestry. On this basis, the International Committee on Taxonomy of Viruses recently established a new order, Nidovirales, to contain the two families. Here, the common traits and distinguishing features of the Nidovirales are reviewed. r 1997 Academic Press KEY WORDS: arterivirus; coronavirus; torovirus; polyprotein processing; RNA recombination.
Vaccinia virus DNA replication occurs in endoplasmic reticulum-enclosed cytoplasmic mini-nuclei
- Mol. Biol. Cell
, 2001
"... Vaccinia virus (vv), a member of the poxvirus family, is unique among most DNA viruses in that its replication occurs in the cytoplasm of the infected host cell. Although this viral process is known to occur in distinct cytoplasmic sites, little is known about its organization and in particular its ..."
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Cited by 16 (0 self)
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Vaccinia virus (vv), a member of the poxvirus family, is unique among most DNA viruses in that its replication occurs in the cytoplasm of the infected host cell. Although this viral process is known to occur in distinct cytoplasmic sites, little is known about its organization and in particular its relation with cellular membranes. The present study shows by electron microscopy (EM) that soon after initial vv DNA synthesis at 2 h postinfection, the sites become entirely surrounded by membranes of the endoplasmic reticulum (ER). Complete wrapping requires �45 min and persists until virion assembly is initiated at 6 h postinfection, and the ER dissociates from the replication sites. [ 3 H]Thymidine incorporation at different infection times shows that efficient vv DNA synthesis coincides with complete ER wrapping, suggesting that the ER facilitates viral replication. Proteins known to be associated with the nuclear envelope in interphase cells are not targeted to these DNA-surrounding ER membranes, ruling out a role for these molecules in the wrapping process. By random green fluorescent protein-tagging of vv early genes of unknown function with a putative transmembrane domain, a novel vv protein, the gene product of E8R, was identified that is targeted to the ER around the DNA sites. Antibodies raised against this vv early membrane protein showed, by immunofluorescence microscopy, a characteristic ring-like pattern around the replication site. By electron microscopy quantitation the protein concentrated in the ER surrounding the DNA site and was preferentially targeted to membrane facing the inside of this site. These combined data are discussed in relation to nuclear envelope assembly/disassembly as it occurs during the cell cycle.
Characterization of defective interfering RNAs of Berne virus
- J. Gen
, 1991
"... were generated by serial undiluted passaging of the virus in embryonic mule skin cells. Two DI RNAs of 1.0 and 1.4 kb (designated DI1000 and DI1400) were characterized in more detail. Isokinetic sucrose gradi-ent analysis howed that these DI RNAs are specifical-ly packaged into particles with smalle ..."
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Cited by 4 (1 self)
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were generated by serial undiluted passaging of the virus in embryonic mule skin cells. Two DI RNAs of 1.0 and 1.4 kb (designated DI1000 and DI1400) were characterized in more detail. Isokinetic sucrose gradi-ent analysis howed that these DI RNAs are specifical-ly packaged into particles with smaller S values than standard virions. Both DI RNAs were cloned and sequenced. Three genomic DNA clones were identi-fied using probes complementary to the 5 ' end of a DI RNA, which are thought to be derived from the 5'-terminal region of the BEV genome. A non-translated region of about 700 nt and the 5 ' end of the putative BEV replicase gene were identified in the consensus nucleotide sequence. Both DI RNAs were shown to contain sequences from the 5 ' and 3 ' ends of the BEV genome. A conserved sequence motif, which has been postulated to be involved in sub-genomic RNA tran-scription, was also identified just downstream of the extreme 5 ' ends of DI1000 and DI1400.
Copyright © 1997, American Society for Microbiology Hemagglutinin-Esterase, a Novel Structural Protein
, 1996
"... We have characterized the 3*-most 3 kb of the genome of bovine torovirus (BoTV) strain Breda. A novel 1.2-kb gene, located between the genes for the membrane and nucleocapsid proteins, was identified. This gene, the 3*-most 0.5 kb of which is also present in the genome of the equine torovirus isolat ..."
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We have characterized the 3*-most 3 kb of the genome of bovine torovirus (BoTV) strain Breda. A novel 1.2-kb gene, located between the genes for the membrane and nucleocapsid proteins, was identified. This gene, the 3*-most 0.5 kb of which is also present in the genome of the equine torovirus isolate Berne virus (BEV), codes for a class I membrane protein displaying 30 % sequence identity with the hemagglutinin-esterases (HEs) of coronaviruses and influenza C viruses. Heterologous expression of the BoTV HE gene yielded a 65,000-molecular weight N-glycosylated protein displaying acetylesterase activity. Serologic evidence indicates that the HE homolog is expressed during the natural infection and represents a prominent antigen. By using an antiserum raised against residues 13 to 130 of HE, the HE protein was detected in radioiodinated, sucrose gradient-purified BoTV preparations. Formal evidence that HE is a structural protein was provided by immunoelectron microscopy. In addition to the large, 17- to 20-nm spikes, BoTV virions possess shorter surface projections (6 nm on average). We postulate that these surface projections, which are absent from the BEV virion, are composed of the BoTV HE homolog. The HE gene, which has now been demonstrated in three different virus genera, is a showpiece example of modular evolution. RNA viruses are genetically very flexible. During the repli-cation of their genomes, nucleotide substitutions occur at a
Review article Toroviruses: replication, evolution and comparison with other members of the coronavirus-like superfamily
"... Based on their morphological and physicochemical characteristics, the Toroviridae were initially proposed to constitute a new family of enveloped RNA viruses (Horzinek & Weiss, 1984; Horzinek et al., 1987). However, recent analysis of the genetic information and replication strategy of the proto ..."
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Based on their morphological and physicochemical characteristics, the Toroviridae were initially proposed to constitute a new family of enveloped RNA viruses (Horzinek & Weiss, 1984; Horzinek et al., 1987). However, recent analysis of the genetic information and replication strategy of the prototype Berne virus (BEV) (Snijder et al., 1988, 1990a, c) has revealed that toro-viruses are not unique: they are clearly related to the Coronaviridae and, more distantly, to the arteriviruses (den Boon et al., 1991 b). This information has led to the reclassification f the toroviruses as a new genus in the coronavirus family (Pringle, 1992) and to the intro-duction of the unofficial term 'coronavirus-like super-family ' to indicate the evolutionary ties between the three virus groups mentioned above. The history of torovirus research not only illustrates the taxonomic onsequences present-day molecular an-alysis may have; the BEV genome has also turned out to be a showcase for the two driving forces in RNA virus evolution: divergence from a common ancestor and RNA recombination (Snijder et al., 1991 a). Comparison of the torovirus genome with those of corona- and arteriviruses has contributed toour understanding of the evolution and replication of all three virus groups. The aim of this review is to present an overview of the data obtained uring the molecular characterization f the torovirus prototype BEV. In addition, evolutionary aspects of our results and their relevance for the classification of toroviruses, coronaviruses and arteri-viruses will be discussed. For information about the clinical and epidemiological spects of toroviruses the reader is referred to a recent review by Koopmans &
Contains the Viral Parental DNA
, 2002
"... This article cites 28 articles, 17 of which can be accessed free ..."
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CONTENT ALERTS
, 1997
"... This article cites 31 articles, 11 of which can be accessed free at: ..."
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Simian Hemorrhagic Fever Virus Genome
, 1994
"... the simian hemorrhagic fever virus genome. Molecular characterization of the 3 ' terminus of ..."
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the simian hemorrhagic fever virus genome. Molecular characterization of the 3 ' terminus of
