New Punctuation for the Genetic Code: Luteovirus Gene Expression

Miller, W. Allen; Brown, Chris M.; Wang, Shanping

doi:10.1006/smvy.1997.0101

Cited by 48 publications

(36 citation statements)

References 87 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Sequences within ORF 5 regulate the translation efficiency of the RT protein, and considerable secondary structure in this region effects transcription and translation (3,18,20). However, no sequences in ORF 3 have been shown to regulate either translation efficiency or the size of the translation product.…”

Section: Resultsmentioning

confidence: 99%

A Surface Loop of the Potato Leafroll Virus Coat Protein Is Involved in Virion Assembly, Systemic Movement, and Aphid Transmission

Lee

Kaplan²,

Ripoll

et al. 2005

J Virol

101

View full text Add to dashboard Cite

Two acidic domains of the Potato leafroll virus (PLRV) coat protein, separated by 55 amino acids and predicted to be adjacent surface features on the virion, were the focus of a mutational analysis. Eleven site-directed mutants were generated from a cloned infectious cDNA of PLRV and delivered to plants by Agrobacterium-mediated mechanical inoculation. Alanine substitutions of any of the three amino acids of the sequence EWH (amino acids 170 to 172) or of D177 disrupted the ability of the coat protein to assemble stable particles and the ability of the viral RNA to move systemically in four host plant species. Alanine substitution of E109, D173, or E176 reduced the accumulation of virus in agrobacterium-infiltrated tissues, the efficiency of systemic infection, and the efficiency of aphid transmission relative to wild-type virus, but the mutations did not affect virion stability. A structural model of the PLRV capsid predicted that the amino acids critical for virion assembly were located within a depression at the center of a coat protein trimer. The other amino acids that affected plant infection and/or aphid transmission were predicted to be located around the perimeter of the depression. PLRV virions play key roles in phloem-limited virus movement in plant hosts as well as in transport and persistence in the aphid vectors. These results identified amino acid residues in a surfaceoriented loop of the coat protein that are critical for virus assembly and stability, systemic infection of plants, and movement of virus through aphid vectors.Members of the family Luteoviridae are icosahedral viruses with small (Ϸ6-kb) RNA genomes that infect phloem-associated tissues of their plant hosts (29). They are transmitted between plants by aphids in a circulative, persistent manner. Although the virus can survive for extended periods in often hostile environments in the aphid, the virus does not replicate in the insect (11). Features of the virion regulate local and systemic movement of the virus in plant hosts and regulate the recognition, transport, and persistence of virus in aphid tissues, yet little is known about the specific properties and biologically active domains of the luteovirus particle.The icosahedral virions of members of the Luteoviridae are composed of two structural proteins, the major 22-to 24-kDa capsid protein (CP) encoded by open reading frame (ORF) 3, and a minor species referred to as the readthrough protein (RT) (17). The RT, encoded by ORF 3 and the downstream adjacent ORF 5, is translated by occasional suppression of the CP termination codon (16). The virion structure has not been resolved for any member of the Luteoviridae, but the capsids are thought to be assembled from 180 subunits according to T ϭ 3 quasi-symmetry. A variable but minor number of the 180 capsids are RT subunits incorporated into the virion via their CP moiety (16), although sequences in the RT domain regulate the incorporation (24). The Ϸ50-kDa RT domain encoded by ORF 5 is believed to protrude from the surface of the virio...

show abstract

Section: Resultsmentioning

confidence: 99%

A Surface Loop of the Potato Leafroll Virus Coat Protein Is Involved in Virion Assembly, Systemic Movement, and Aphid Transmission

Lee

Kaplan²,

Ripoll

et al. 2005

J Virol

101

View full text Add to dashboard Cite

show abstract

“…Studies of PAV have provided fascinating insight into mechanisms of decoding the genetic code not known previously in any organism (69). Structurefunction analyses of the self-cleavage structure in the satellite RNA of RPV (74) contributed to understanding of the three-dimensional structure of hammerhead ribozymes (15).…”

Section: Discussionmentioning

confidence: 99%

Barley Yellow Dwarf Viruses

Miller

Rasochova²

1997

Annu. Rev. Phytopathol.

215

154

View full text Add to dashboard Cite

Barley yellow dwarf viruses represent one of the most economically important and ubiquitous groups of plant viruses. This review focuses primarily on four research areas in which progress has been most rapid. These include (a) evidence supporting reclassification of BYDVs into two genera; (b) elucidation of gene function and novel mechanisms controlling gene expression; (c) initial forays into understanding the complex interactions between BYDV virions and their aphid vectors; and (d ) replication of a BYDV satellite RNA. Economic losses, symptomatology, and means of control of BYD are also discussed.

show abstract

“…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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

New Punctuation for the Genetic Code: Luteovirus Gene Expression

Cited by 48 publications

References 87 publications

A Surface Loop of the Potato Leafroll Virus Coat Protein Is Involved in Virion Assembly, Systemic Movement, and Aphid Transmission

A Surface Loop of the Potato Leafroll Virus Coat Protein Is Involved in Virion Assembly, Systemic Movement, and Aphid Transmission

Barley Yellow Dwarf Viruses

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

Contact Info

Product

Resources

About