Evidence that Potato Leafroll Virus RNA is Positive-stranded, is Linked to a Small Protein and Does Not Contain Polyadenylate

Mayo, M. A.; Barker, H. A.; Robinson, David J.; Tamada, T.; Harrison, B. D.

doi:10.1099/0022-1317-59-1-163

Cited by 77 publications

(50 citation statements)

References 7 publications

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“…The 39 end of mRNA also participates in translation initiation (Gallie, 1991;Tarun & Sachs, 1995;Jacobson, 1996;Sachs et al+, 1997)+ The poly(A) tail interacts synergistically with the 59 cap in stimulating translation in vivo (Gallie, 1991; Tarun et al+, 1997; Preiss & Hentze, 1998)+ In viral RNAs that lack a 39 poly(A) tail, other sequences in the 39 UTR may stimulate translation (Leathers et al+, 1993)+ The RNAs of barley yellow dwarf virus (BYDV; Allen et al+, 1999) and satellite tobacco necrosis virus (STNV; Lesnaw & Reichmann, 1970) lack both a 59 cap and a poly(A) tail+ The RNAs of these viruses each contain a different sequence in the 39 UTR that confers efficient cap-independent translation on uncapped mRNA (Danthinne et al+, 1993;Timmer et al+, 1993;Wang & Miller, 1995;Wang et al+, 1997;Meulewaeter et al+, 1998)+ BYDV is in the genus Luteovirus of the family Luteoviridae+ Members of the family Luteoviridae have a single stranded, positive-sense RNA genome of 5+6 to 5+7 kb encoding about six open reading frames (ORFs) (Mayo & Ziegler-Graff, 1996;Miller, 1999)+ Viruses in the genus Polerovirus of the family Luteoviridae have a VPg linked to the 59 terminus of the genome (Mayo et al+, 1982;Murphy et al+, 1989), whereas BYDV RNA has neither a VPg (Shams-bakhsh & Symons, 1997) nor a 59 cap (Allen et al+, 1999)+ During its life cycle, BYDV produces three subgenomic RNAs (sgRNAs) that are 39 coterminal with genomic RNA (gRNA) (Fig+ 1) (Kelly et al+, 1994;Mohan et al+, 1995;Miller et al+, 1997)+ The ORFs (1 and 2) in the 59 half of genome are translated from gRNA (Wang & Miller, 1995)+ ORF 2, which encodes the RNA-dependent RNA polymerase, is translated by ribosomal frameshifting from ORF 1 to generate a 99-kDa fusion product (Di et al+, 1993)+ ORFs 3, 4, and 5 code for the coat protein, movement protein, and an aphid transmission function, respectively (reviewed by Miller, 1999)+ All three ORFs are translated only from sgRNA1 (Fig+ 1) (Brown et al+, 1996)+ ORF 4 is translated by leaky scanning (Dinesh-Kumar & Miller, 1993) and ORF 5 by in-frame readthrough of the ORF 3 stop codon (Brown et al+, 1996)+ Subgenomic RNA2 (sgRNA2) may serve as a message for ORF 6 (K...…”

Section: Introductionmentioning

confidence: 99%

A potential mechanism for selective control of cap-independent translation by a viral RNA sequence in cis and in trans

Wang

Guo

Allen

et al. 1999

RNA

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Highly efficient cap-independent translation initiation at the 59-proximal AUG is facilitated by the 39 translation enhancer sequence (39TE) located near the 39 end of barley yellow dwarf virus (BYDV) genomic RNA. The role of the 39TE in regulating viral translation was examined. The 39TE is required for translation and thus replication of the genomic RNA that lacks a 59 cap (Allen et al., 1999, Virology 253:139-144). Here we show that the 39TE also mediates translation of uncapped viral subgenomic mRNAs (sgRNA1 and sgRNA2). A 109-nt viral sequence is sufficient for 39TE activity in vitro, but additional viral sequence is necessary for cap-independent translation in vivo. The 59 extremity of the sequence required in the 39 untranslated region (UTR) for cap-independent translation in vivo coincides with the 59 end of sgRNA2. Thus, sgRNA2 has the 39TE in its 59 UTR. Competition studies using physiological ratios of viral RNAs showed that, in trans, the 109-nt 39TE alone, or in the context of 869-nt sgRNA2, inhibited translation of genomic RNA much more than it inhibited translation of sgRNA1. The divergent 59 UTRs of genomic RNA and sgRNA1 contribute to this differential susceptibility to inhibition. We propose that sgRNA2 serves as a novel regulatory RNA to carry out the switch from early to late gene expression. Thus, this new mechanism for temporal control of translation control involves a sequence that stimulates translation in cis and acts in trans to selectively inhibit translation of viral mRNA.

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Section: Introductionmentioning

confidence: 99%

A potential mechanism for selective control of cap-independent translation by a viral RNA sequence in cis and in trans

Wang

Guo

Allen

et al. 1999

RNA

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“…The virus is transmitted in a persistent manner by aphids into the host plant where it replicates specifically in the phloem tissue (Francki et al, 1985). The genomic singlestranded, non-polyadenylated RNA is approximately 6 kb in size and possesses a genome-linked small protein (VPg; Mayo et al, 1982;Harrison, 1984). Sequence analysis has revealed the presence of six large open reading frames (ORFs) in two gene clusters separated by a small intergenic region (Mayo et al, 1989;van der Wilk et al, 1989;Keese et al, 1990;Fig.…”

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confidence: 99%

The Potato Leafroll Luteovirus 17K Protein is a Single-stranded Nucleic Acid-binding Protein

Tacke

Prüfer

Schmitz

et al. 1991

Journal of General Virology

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Section: Discussionmentioning

confidence: 99%

“…Both tobacco necrotic dwarf virus (TNDV) and potato leafroU virus (PLRV) can infect a high percentage of isolated tobacco mesophyll protoplasts (Kubo & Takanami, 1979). In addition, isolated RNA from PLRV has been demonstrated to be infectious for tobacco protoplasts (Mayo et al, 1982).Attempts to develop a similar bioassay system for BYDV expression have resulted in only limited success. The work of Barnett et al (1981) suggests a low level of infection of cereal protoplasts with the BYDV MAV serotype.…”

mentioning

confidence: 99%

Infection of Triticum monococcum Protoplasts with Barley Yellow Dwarf Virus

Young

Larkin

Miller³

et al. 1989

Journal of General Virology

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SUMMARYProtoplasts from a Triticum monococcum cell culture line were successfully infected with barley yellow dwarf virus. Both purified virions and extracted RNA were shown to be infectious using a polyethylene glycol inoculation procedure. Up to 209/00 of the protoplasts contained viral antigens as judged by immunofluorescence assay. ELISA analysis showed that virus antigen expression was both dose-and time-dependent. Synthesis of new viral RNAs was confirmed by Northern blot hybridization. Studies of the expression of this economically important aphid-borne, phloem-limited virus should be greatly facilitated using this graminaceous protoplast system. It is the first reproducible protoplast infection system for this virus which can not be transmitted mechanically at the whole plant level.Barley yellow dwarf virus (BYDV) is a member of the luteovirus group and can cause significant economic losses to cereals (Bumett, 1984;Waterhouse et al., 1988). The luteovirus group is characteristically aphid-transmitted in a persistent manner and phloem-limited in infected plants. BYDV has 25 nm icosahedral particles with a single-stranded RNA genome of approx. Mr 2 x 106. Unlike many other plant viruses, luteoviruses are not mechanically transmissible. BYDV is currently divided into five serotypes on the basis of the specificity of its aphid vector and serological properties of the virions. Although the sequence of the genome of the PAV serotype of BYDV has been recently completed (Miller et al., 1988) there is still little biochemical information available on the replication and host interactions of this virus. This is due in part to the difficulties associated with the low yields produced and with working with a phloem-limited virus in plants.Protoplast infection systems have been described for two luteoviruses which infect dicotyledonous plants but none has been developed for BYDV, which infects monocotyledons. Both tobacco necrotic dwarf virus (TNDV) and potato leafroU virus (PLRV) can infect a high percentage of isolated tobacco mesophyll protoplasts (Kubo & Takanami, 1979). In addition, isolated RNA from PLRV has been demonstrated to be infectious for tobacco protoplasts (Mayo et al., 1982).Attempts to develop a similar bioassay system for BYDV expression have resulted in only limited success. The work of Barnett et al. (1981) suggests a low level of infection of cereal protoplasts with the BYDV MAV serotype. These investigators concluded that the large variability and low level of infection which they observed made such an approach unsuitable as a useful bioassay for BYDV replication. The techniques described here establish for the first time an effective and routine method for infection of monocotyledonous protoplasts with BYDV virions or RNA.A Triticum monococcum cell culture system provided a convenient and reliable source of graminaceous protoplasts suitable for infection with BYDV. A suspension cell culture line of T. monococcum was obtained from H. Lorz (K61n, F.R.G.) and maintained in WtMI medium t Present a...

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Evidence that Potato Leafroll Virus RNA is Positive-stranded, is Linked to a Small Protein and Does Not Contain Polyadenylate

Cited by 77 publications

References 7 publications

A potential mechanism for selective control of cap-independent translation by a viral RNA sequence in cis and in trans

A potential mechanism for selective control of cap-independent translation by a viral RNA sequence in cis and in trans

The Potato Leafroll Luteovirus 17K Protein is a Single-stranded Nucleic Acid-binding Protein

Infection of Triticum monococcum Protoplasts with Barley Yellow Dwarf Virus

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