The nucleotide sequence of the M RNA segment of tomato spotted wilt virus, a bunyavirus with two ambisense RNA segments

Abstract

The complete sequence of the tomato spotted wilt virus (TSWV) M RNA segment has been determined. The RNA is 4821 nucleotides long and has an ambisense coding strategy similar to that of the S RNA segment. The M RNA segment contains two open reading frames (ORFs), one in the viral sense which encodes a protein with a predicted size of 33-6K, and one in the viral complementary sense which encodes the precursor to the G 1 and G2 glycoproteins, with a predicted size of 127.4K. Both ORFs are expressed via the synthesis of subgenomic mRNAs that possibly terminate at a stable hairpin structure, located in the intergenic region. The precursor for the glycoproteins contains a sequence motif (RGD) which is characteristic of cellular attachment domains. Significant sequence homology was found between the G1 glycoproteins of members of the genus Bunyavirus and a corresponding region in the glycoprotein precursor of TSWV, indicating a close evolutionary relationship between these viruses. With the elucidation of the M RNA sequence, the complete nucleotide sequence of TSWV has been determined. TSWV represents the first member of the Bunyaviridae shown to contain two ambisense RNA segments.

Viral genetic determinants for thrips transmission of Tomato spotted wilt virus

“…The formation of enveloped virions and detectable G C in host plants infected with each of the nontransmissible SLIs that had only the C1375A mutation in the G N ͞G C ORF suggests that the loss of thrips transmissibility by these mutants may not be due to a change in synthesis of the proteins. The mutation is also outside the RGD motif of G N ͞G C ORF, which has been associated with cellular attachment in some animal pathogens (18,(44)(45)(46). The C1375A mutation may not be involved with glycoprotein processing, even though there is a previous report that amino acid 484 of TSWV G N ͞G C may be a cleavage site within the glycoprotein precursor (47).…”

“…The M RNA sequence of TSWV-RG2P24 and SLIs originating from this isolate were determined by RT-PCR and cycle sequencing of overlapping PCR products. The PCR primers were chosen from a published sequence of TSWV isolate BR-01 (18) and are shown in Table 3, which is published as supporting information on the PNAS web site. Amplification of intergenic region was conducted as described (34).…”

“…The L RNA is of negative polarity and encodes an RNA-dependent RNA polymerase (RdRp) (15,16). The putative cell-to-cell movement protein (NSm) and the precursor of surface glycoproteins on the envelope (G N ͞G C ) are encoded by the M RNA in the viral and viral complementary sense, respectively (17,18). The glycoprotein precursor is further glycosylated and cleaved into two glycoproteins, G N and G C , by an unknown mechanism (19).…”

High affinity recognition of a Phytophthora protein by Arabidopsis via an RGD motif

“…So far, very few RGD-containing proteins from plant pathogens have been described. We know of one virus protein, the precursor of G1 and G2 glycoproteins of the tomato spotted wilt virus [30]; two fungal proteins, ECP5 from Cladosporium fulvum [31] and Ptr ToxA from Pyrenophora tritici-repentis [14]; and one oomycete protein, IPI-O from Phytophthora infestans [19]. ECP5, Ptr ToxA and IPI-O are secreted proteins and also G1 and G2 are located outside the virus namely in the virus envelope membrane.…”

The movement protein NSm of tomato spotted wilt tospovirus (TSWV): RNA binding, interaction with the TSWV N protein, and identification of interacting plant proteins

“…The S RNA encodes the nonstructural protein NSs of unknown function and the N protein, the main constituent of the nucleocapsid, which is known to bind RNA and to form homooligomeric structures (6 -8). The spike glycoproteins G1 and G2 and the putative movement protein NSm are encoded by the ambisense M RNA (9).…”