Morphogenesis of Sonchus yellow net virus in cowpea protoplasts

Beek, N.A.M. van; Lohuis, Dick; Dijkstra, Jeanne; Peters, D.

doi:10.1016/s0022-5320(85)80007-1

Cited by 31 publications

(30 citation statements)

References 16 publications

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“…8, SYNV). Treatment with the glycosylation inhibitor tunicamycin results in almost complete inhibition of nucleorhabdovirus budding and leads to accumulation of nucleocapsid cores in the nucleus (41), thus supporting the proposed model. The various results obtained in the present study suggest a similar but distinct model for OFV replication and assembly, as follows (Fig.…”

Section: Figsupporting

confidence: 71%

“…1H, arrow), unlike previous reports for SYNV and PYDV (2,39,40). Such nuclear accumulation of ER membranes is believed to be required for SYNV maturation (budding) from the nuclear side into the perinuclear space (41). The virion budding of OFV into the perinuclear space appears to be less efficient than that in nucleorhabdoviruses (11,13), and thus, OFV infection may not induce drastic relocalization of the cellular membrane of N. benthamiana cells.…”

Section: Discussionmentioning

confidence: 77%

See 1 more Smart Citation

Orchid Fleck Virus Structural Proteins N and P Form Intranuclear Viroplasm-Like Structures in the Absence of Viral Infection

Kondō

Chiba

Andika

et al. 2013

J Virol

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bOrchid fleck virus (OFV) has a unique two-segmented negative-sense RNA genome that resembles that of plant nucleorhabdoviruses. In infected plant cells, OFV and nucleorhabdoviruses induce an intranuclear electron-lucent viroplasm that is believed to be the site for virus replication. In this study, we investigated the molecular mechanism by which OFV viroplasms are produced in vivo. Among OFV-encoded proteins, the nucleocapsid protein (N) and the putative phosphoprotein (P) were present in nuclear fractions of OFV-infected Nicotiana benthamiana plants. Transient coexpression of N and P, in the absence of virus infection, was shown to be sufficient for formation of an intranuclear viroplasm-like structure in plant cells. When expressed independently as a fluorescent protein fusion product in uninfected plant cells, N protein accumulated throughout the cell, while P protein accumulated in the nucleus. However, the N protein, when coexpressed with P, was recruited to a subnuclear region to induce a large viroplasm-like focus. Deletion and substitution mutagenesis demonstrated that the P protein contains a nuclear localization signal (NLS). Artificial nuclear targeting of the N-protein mutant was insufficient for formation of viroplasm-like structures in the absence of P. A bimolecular fluorescence complementation assay confirmed interactions between the N and P proteins within subnuclear viroplasm-like foci and interactions of two of the N. benthamiana importin-␣ homologues with the P protein but not with the N protein. Taken together, our results suggest that viroplasm formation by OFV requires nuclear accumulation of both the N and P proteins, which is mediated by P-NLS, unlike nucleorhabdovirus viroplasm utilizing the NLS on protein N. R habdoviruses (family Rhabdoviridae, order Mononegavirales) have a broad range of hosts, including humans, livestock, fish, plants, and insects (1). They have bacilliform or bulletshaped virions containing a nonsegmented negative-sense RNA [(Ϫ)RNA] as the genome (2). All of the well-characterized animal rhabdoviruses replicate in the cytoplasm (1). However, the plant rhabdoviruses are divided into two groups, depending on their sites of replication and morphogenesis. Members of the genus Cytorhabdovirus replicate and undergo morphogenesis in the cytoplasm, whereas members of the genus Nucleorhabdovirus multiply in plant cell nuclei and their virions bud through the inner nuclear envelopes (3, 4).Orchid fleck virus (OFV), a Brevipalpus (Acari: Tenuipalpidae) mite-transmitted virus, has a unique two-segmented (Ϫ)RNA genome that resembles that of plant rhabdoviruses (5, 6). OFV is distributed worldwide and infects many kinds of orchids (5,7,8). OFV RNA1 (GenBank accession number AB244417; 6,413 nucleotides [nt]) contains five genes in the order 3=-N-P-3-M-G-5=, in which N encodes the nucleocapsid protein (open reading frame 1 [ORF1]), P encodes the phosphoprotein (ORF2), gene 3 encodes the candidate movement protein (ORF3), M encodes the matrix protein (ORF4), and G encodes the can...

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Section: Figsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 77%

Orchid Fleck Virus Structural Proteins N and P Form Intranuclear Viroplasm-Like Structures in the Absence of Viral Infection

Kondō

Chiba

Andika

et al. 2013

J Virol

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“…In a previous report, we have shown that incubation of infected protoplasts in tunicamycin completely prevented budding of SYNV (van Beek et al, 1985b). G protein may therefore be involved in the budding process.…”

Section: Synthesis Of S Ynv Proteins In Protoplastsmentioning

confidence: 71%

Synthesis of Sonchus Yellow Net Virus Proteins in Infected Cowpea Protoplasts

Beek¹,

Derksen²,

Dijkstra³

1986

Journal of General Virology

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SUMMARYWe studied protein synthesis in cowpea protoplasts infected with Sonchus yellow net virus (SYNV). The structural viral proteins G, N, M1 and M2 were identified by immunoprecipitation. In addition, four high molecular weight proteins and two proteins with molecular weights of 52 000 (p52) and 38 000 (p38) were precipitated. One of the four high molecular weight proteins may represent the L protein; the others are possibly aggregates of the G protein or its unglycosylated form. The nature of proteins p52 and p38 is unclear. Structural viral proteins first appeared between 8 h and 12 h after inoculation. The G protein is glycosylated by N-glycoside-linked sugar residues. Glycosylation of the G protein was prevented by incubation of the protoplasts in 10 gg/ml tunicamycin. A protein, co-migrating with the M1 protein, was labelled with [32p]orthophosphate in protoplasts infected with SYNV, but not in controls of mockinoculated protoplasts or protoplasts inoculated with cowpea mosaic virus. INTRODUCTIONThe protein composition of plant rhabdoviruses has been studied by several authors

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“…It is possible that preparations of FLSV particles contained fewer infective particles than preparations of SYNV. Also, the number of FLSV particles formed in each infected protoplast was less than the number of SYNV particles formed in cowpea protoplasts (Van Beek et al, 1985b) and less than the number of particles found in cells ofF. gigantea leaves systemically infected with FLSV (Lundsgaard & Albrechtsen, 1979).…”

Section: S H O R T C O M M U N I C a T I Omentioning

confidence: 80%

“…However, inocula of FLSV infected fewer cowpea protoplasts than did inocula of SYNV (Van Beek et al, 1985b). It is possible that preparations of FLSV particles contained fewer infective particles than preparations of SYNV.…”

Section: S H O R T C O M M U N I C a T I Omentioning

confidence: 99%