Cowpea mosaic virus (CPMV) replicates in close association with small membranous vesicles that are formed by rearrangements of intracellular membranes. To determine which of the viral proteins are responsible for the rearrangements of membranes and the attachment of the replication complex, we have expressed individual CPMV proteins encoded by RNA1 in cowpea protoplasts by transient expression and in Nicotiana benthamiana plants by using the tobacco rattle virus (TRV) expression vector. The 32-kDa protein (32K) and 60K, when expressed individually, accumulate in only low amounts but are found associated with membranes mainly derived from the endoplasmic reticulum (ER). 24K and 110K are freely soluble and accumulate to high levels. With the TRV vector, expression of 32K and 60K results in rearrangement of ER membranes. Besides, expression of 32K and 60K results in necrosis of the inoculated N. benthamiana leaves, suggesting that 32K and 60K are cytotoxic proteins. On the other hand, during CPMV infection 32K and 60K accumulate to high levels without causing necrosis.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC136232 | PMC |
| http://dx.doi.org/10.1128/jvi.76.12.6293-6301.2002 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Cowpea mosaic virus 32- and 60-kilodalton replication proteins target and change the morphology of endoplasmic reticulum membranes.
J Virol
June 2002
Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands.
Cowpea mosaic virus (CPMV) replicates in close association with small membranous vesicles that are formed by rearrangements of intracellular membranes. To determine which of the viral proteins are responsible for the rearrangements of membranes and the attachment of the replication complex, we have expressed individual CPMV proteins encoded by RNA1 in cowpea protoplasts by transient expression and in Nicotiana benthamiana plants by using the tobacco rattle virus (TRV) expression vector. The 32-kDa protein (32K) and 60K, when expressed individually, accumulate in only low amounts but are found associated with membranes mainly derived from the endoplasmic reticulum (ER).
View Article and Find Full Text PDFSynthesis of the complete 200K polyprotein encoded by cowpea mosaic virus B-RNA in insect cells.
J Gen Virol
November 1992
Department of Molecular Biology, Agricultural University, Dreyenlaan, Wageningen, The Netherlands.
The coding sequence for the entire 200K polyprotein of cowpea mosaic virus (CPMV) B-RNA was expressed in insect cells by using baculovirus expression vectors. The 200K polyprotein, which harbours all virus functions required for RNA replication, is completely cleaved into 170K and 32K products by the 24K protease activity contained within the polyprotein. Further processing of the 170K protein into CPMV-specific products of 60K, 84K, 87K, 110K and 112K occurred to a limited extent, similar to that observed in cowpea cells.
View Article and Find Full Text PDFProcessing of VPg-containing polyproteins encoded by the B-RNA from cowpea mosaic virus.
Virology
November 1992
Department of Molecular Biology, Agricultural University, Wageningen, The Netherlands.
To study the processing of putative VPg precursors the expression of specific mutant transcripts derived from a full-length cDNA clone of cowpea mosaic virus (CPMV) B-RNA was examined in a rabbit reticulocyte lysate system. This study revealed that the 170K protein produced by a B-RNA mutant that lacks the 32K coding region was efficiently processed by mainly intramolecular cleavages at three different sites into three sets of proteins of 60K + 110K, 84K + 87K, and 58K + 112K. Further cleavage of the 60K protein into 58K and VPg has not been observed in this in vitro system.
View Article and Find Full Text PDFA regulatory role for the 32K protein in proteolytic processing of cowpea mosaic virus polyproteins.
Virology
November 1992
Department of Molecular Biology, Agricultural University, Wageningen, The Netherlands.
We have studied the regulation of proteolytic processing of the polyproteins encoded by cowpea mosaic virus M-RNA and B-RNA. For that purpose mutations were introduced in full-length cDNA clones of these RNAs. RNA transcripts were translated in rabbit reticulocyte lysate and the effect of mutations on the processing was analysed.
View Article and Find Full Text PDF[Purification and characterization of insulin-like growth factor binding proteins (IGF-BP) in amniotic fluid--existence of a 160K IGF-BP].
Nihon Naibunpi Gakkai Zasshi
June 1990
Maternal and Perinatal Center, Tokyo Women's Medical College, Japan.
Human amniotic fluid has been reported to contain 28-34K insulin-like growth factor (IGF) binding protein (32K-AFBP). The existence of 160K IGF-binding protein (160K-AFBP) in amniotic fluid was also demonstrated by affinity labeling studies. In this paper we describe procedures for purification of 160K-AFBP as well as 32K-AFBP from pre-term amniotic fluid and characterize these two binding proteins.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!