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Closterovirus encoded HSP70 homolog and p61 in addition to both coat proteins function in efficient virion assembly
Year:
2000
Source of publication :
Virology
Authors :
Mawassi, Munir
;
.
Volume :
278
Co-Authors:
Satyanarayana, T., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Gowda, S., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Mawassi, M., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Albiach-Martí, M.R., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Ayllón, M.A., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Robertson, C., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Garnsey, S.M., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Dawson, W.O., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Facilitators :
From page:
253
To page:
265
(
Total pages:
13
)
Abstract:
Assembly of the viral genome into virions is a critical process of the virus life cycle often defining the ability of the virus to move within the plant and to be transmitted horizontally to other plants. Closteroviridae virions are polar helical rods assembled primarily by a major coat protein, but with a related minor coat protein at one end. The Closteroviridae is the only virus family that encodes a protein with similarity to cellular chaperones, a 70-kDa heat-shock protein homolog (HSP70h). We examined the involvement of gene products of Citrus tristeza virus (CTV) in virion formation and found that the chaperone-like protein plus the p61 and both coat proteins were required for efficient virion assembly. Competency of virion assembly of different CTV mutants was assayed by their ability to be serially passaged in Nicotiana benthamiana protoplasts using crude sap as inoculum, and complete and partial virus particles were analyzed by serologically specific electron microscopy. Deletion mutagenesis revealed that p33, p6, p18, p13, p20, and p23 genes were not needed for virion formation. However, deletion of either minor- or major-coat protein resulted in formation of short particles which failed to be serially transferred in protoplasts, suggesting that both coat proteins are required for efficient virion assembly. Deletion or mutation of HSP70h and/or p61 dramatically reduced passage and formation of full-length virions. Frameshift mutations suggested that the HSP70h and p61 proteins, not the RNA sequences, were needed for virion assembly. Substitution of the key amino acid residues in the ATPase domain of HSP70h, Asp7 to Lys or Glu180 to Arg, reduced assembly, suggesting that the chaperone-like ATPase activity is involved in assembly. Both HSP70h and p61 proteins appeared to contribute equally to assembly, consistent with coordinate functions of these proteins in closterovirus virion formation. The requirement of two accessory proteins in addition to both coat proteins for efficient assembly is uniquely complex for helical virions. (C) 2000 Academic Press.
Note:
Related Files :
amino acid
chaperone
Citrus tristeza virus
HSP70 Heat-Shock Proteins
Open reading frame
Plants
virus genome
virus particle
Show More
Related Content
More details
DOI :
10.1006/viro.2000.0638
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
29579
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:48
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Scientific Publication
Closterovirus encoded HSP70 homolog and p61 in addition to both coat proteins function in efficient virion assembly
278
Satyanarayana, T., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Gowda, S., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Mawassi, M., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Albiach-Martí, M.R., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Ayllón, M.A., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Robertson, C., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Garnsey, S.M., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Dawson, W.O., Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, United States
Closterovirus encoded HSP70 homolog and p61 in addition to both coat proteins function in efficient virion assembly
Assembly of the viral genome into virions is a critical process of the virus life cycle often defining the ability of the virus to move within the plant and to be transmitted horizontally to other plants. Closteroviridae virions are polar helical rods assembled primarily by a major coat protein, but with a related minor coat protein at one end. The Closteroviridae is the only virus family that encodes a protein with similarity to cellular chaperones, a 70-kDa heat-shock protein homolog (HSP70h). We examined the involvement of gene products of Citrus tristeza virus (CTV) in virion formation and found that the chaperone-like protein plus the p61 and both coat proteins were required for efficient virion assembly. Competency of virion assembly of different CTV mutants was assayed by their ability to be serially passaged in Nicotiana benthamiana protoplasts using crude sap as inoculum, and complete and partial virus particles were analyzed by serologically specific electron microscopy. Deletion mutagenesis revealed that p33, p6, p18, p13, p20, and p23 genes were not needed for virion formation. However, deletion of either minor- or major-coat protein resulted in formation of short particles which failed to be serially transferred in protoplasts, suggesting that both coat proteins are required for efficient virion assembly. Deletion or mutation of HSP70h and/or p61 dramatically reduced passage and formation of full-length virions. Frameshift mutations suggested that the HSP70h and p61 proteins, not the RNA sequences, were needed for virion assembly. Substitution of the key amino acid residues in the ATPase domain of HSP70h, Asp7 to Lys or Glu180 to Arg, reduced assembly, suggesting that the chaperone-like ATPase activity is involved in assembly. Both HSP70h and p61 proteins appeared to contribute equally to assembly, consistent with coordinate functions of these proteins in closterovirus virion formation. The requirement of two accessory proteins in addition to both coat proteins for efficient assembly is uniquely complex for helical virions. (C) 2000 Academic Press.
Scientific Publication
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