Structure of the glycoprotein gene of sonchus yellow net virus, a plant rhabdovirus

Abstract

The nucleotide sequence of the glycoprotein (G) gene of sonchus yellow net virus (SYNV), a plant rhabdovirus, was determined from viral genomic and mRNA cDNA clones. The G cistron is 2045 nucleotides (nt) long and the G protein mRNA open reading frame (ORF), as determined from the cDNA sequence, contains 1896 nt and encodes a protein of 632 amino acids. Immunoblots with antibodies elecited against the purified glycoprotein from virus particles reacted with a fusion protein produced in Escherichia coli, indicating that the cloned ORF encodes the G protein. The 5' end of the G protein mRNA corresponds to nt 5111, relative to the 3' end of the viral (minus sense) genome, as determined by primer extension from mRNA isolated from infected plants, and extends to nt position 7155 on the genomic RNA. A 34-nt untranslated 5' leader sequence and a 115-nt untranslated 3' end flank the ORF on the mRNA. The gene junctions on either side of the G gene on the genomic RNA are identical to those previously described for other SYNV genes and are similar to sequences separating genes of animal rhabdoviruses. The predicted molecular weight of the G protein is 70,215 Da, a value less than the 77,000 Da estimated for the glycosylated G protein from virus particles. The deduced amino acid sequence of the SYNV G protein shares little direct relatedness with the G proteins of other rhabdoviruses, but appears to contain a similar signal sequence, a transmembrane anchor domain, and glycosylation signals. In addition, the SYNV G protein contains a putative nuclear targeting site near the carboxy terminus, which may be involved in transit to the nuclear membrane prior to morphogenesis.

Plant Immune Responses Against Viruses: How Does a Virus Cause Disease?

“…By definition, viruses do not possess conserved P/MAMP-like features such as flagellin or chitin. However, structures such as, but not limited to, the virion (or capsid), viral ribonucleoprotein complexes, and viral-encoded glycoproteins embedded on the host-derived lipid membranes of plant rhabdoviruses (Goldberg et al, 1991;Jackson et al, 2005) are analogous to P/MAMPs. Importantly, these structures are conserved among members of related virus taxa.…”

New Gateways to Discovery

“…For example, our attempts to express the sonchus yellow net virus (SYNV) glycoprotein by fusing RFP to its C terminus were unsuccessful. Despite the fact that SYNV glycoprotein contains a predicted N-terminal signal peptide (Goldberg et al, 1991), the correctly targeted fusion was that in which RFP was placed in frame ahead of the signal peptide . In a more detailed study, Simpson et al (2001) found that approximately 50% of human proteins, including those targeted to the ER or mitochondria, localized to the same subcellular locus when expressed as N-terminal fusions to CFP or C-terminal fusions to YFP (Pepperkok and Ellenberg, 2006).…”

Interactions and Nuclear Import of the N and P Proteins of Sonchus Yellow Net Virus, a Plant Nucleorhabdovirus

“…The membrane fraction contains a glycoprotein (G) that protrudes from the surface of the virion (11) and an associated protein designated sc4 (46). The membrane fraction also contains an additional protein that is thought to be an analogue of the matrix protein (M) of the animal-infecting prototype rhabdovirus, Vesicular stomatitis virus (VSV) (16), which associates with the G protein and the nucleocapsid core during morphogenesis to stabilize the virus particle.…”