RNA-binding activities of barley stripe mosaic virus  b fusion proteins

Donald, Robert G. K.; Jackson, A.O.

doi:10.1099/0022-1317-77-5-879

Cited by 45 publications

(37 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, although BSMV ␥B and HC-Pro are very dissimilar, both suppressors contain a cysteine-rich region that might form a zinc finger motif (1,7,17,29,52). It is tempting to speculate that zinc finger domains play important roles in the ds-sRNA binding of BSMV ␥B and HC-Pro.…”

Section: Discussionmentioning

confidence: 99%

Double-Stranded RNA Binding May Be a General Plant RNA Viral Strategy To Suppress RNA Silencing

Mérai

Kerényi

Kertész

et al. 2006

J Virol

277

255

View full text Add to dashboard Cite

In plants, RNA silencing (RNA interference) is an efficient antiviral system, and therefore successful virus infection requires suppression of silencing. Although many viral silencing suppressors have been identified, the molecular basis of silencing suppression is poorly understood. It is proposed that various suppressors inhibit RNA silencing by targeting different steps. However, as double-stranded RNAs (dsRNAs) play key roles in silencing, it was speculated that dsRNA binding might be a general silencing suppression strategy. Indeed, it was shown that the related aureusvirus P14 and tombusvirus P19 suppressors are dsRNA-binding proteins. Interestingly, P14 is a size-independent dsRNA-binding protein, while P19 binds only 21-nucleotide ds-sRNAs (small dsRNAs having 2-nucleotide 3 overhangs), the specificity determinant of the silencing system. Much evidence supports the idea that P19 inhibits silencing by sequestering silencing-generated viral ds-sRNAs. In this study we wanted to test the hypothesis that dsRNA binding is a general silencing suppression strategy. Here we show that many plant viral silencing suppressors bind dsRNAs. Beet yellows virus Peanut P21, clump virus P15, Barley stripe mosaic virus ␥B, and Tobacco etch virus HC-Pro, like P19, bind ds-sRNAs size-selectively, while Turnip crinkle virus CP is a size-independent dsRNA-binding protein, which binds long dsRNAs as well as ds-sRNAs. We propose that size-selective ds-sRNA-binding suppressors inhibit silencing by sequestering viral ds-sRNAs, whereas size-independent dsRNA-binding suppressors inactivate silencing by sequestering long dsRNA precursors of viral sRNAs and/or by binding ds-sRNAs. The findings that many unrelated silencing suppressors bind dsRNA suggest that dsRNA binding is a general silencing suppression strategy which has evolved independently many times.RNA silencing (termed RNA interference [RNAi] in animals) is an RNA-based eukaryotic gene regulatory system that plays essential roles in many biological processes. RNA silencing is induced by accumulation of double-stranded RNAs (dsRNAs). dsRNAs are first processed by an RNase III-like nuclease called DICER (in plants it is termed DICER-LIKE [DCL]) into (21-to 25-nucleotide [nt]) small dsRNAs (ds-sRNAs) having 2-nt 3Ј overhangs, and then these sRNAs incorporate into different silencing effector complexes. In the active effector complexes sRNAs are present as single-stranded molecules, which guide these complexes to the complementary nucleic acids for suppression (2, 3, 22, 61).In plants, different dsRNA precursors are processed by distinct DCLs into functionally different short (21-to 22-nt) and long (23-to 25-nt) sRNAs (24, 25, 67). Short sRNAs guide a multicomponent nuclease (RNA-induced silencing complex [RISC]) to homologous mRNAs for suppression. RISC cleaves targeted mRNA in the case of (near) perfect base pairing between mRNA and guide RNA. When the guide RNA is only partially complementary to the mRNA, RISC mediates translational repression. Short sRNAs could also provide ...

show abstract

Section: Discussionmentioning

confidence: 99%

Double-Stranded RNA Binding May Be a General Plant RNA Viral Strategy To Suppress RNA Silencing

Mérai

Kerényi

Kertész

et al. 2006

J Virol

277

255

View full text Add to dashboard Cite

show abstract

“…The amino acids targeted in the BM were previously found to be important for in vitro RNA-binding activity (5). Substitution of arginine and lysine residues within BM resulted in diverse disease phenotypes when the mutant RNA␥ derivatives were inoculated onto plants (4,5).…”

Section: Species Of ␥B Corresponding To Sizes Expected For Monomers (mentioning

confidence: 99%

“…Although a Factor Xa protease cleavage recognition site had been inserted between the MBP sequence and the ␥b sequence for each construct, the protease failed to release ␥b from the fusion proteins even after extensive digestion under a variety of conditions (data not shown). A similar problem was encountered with attempted thrombin digestion of the GST-␥b fusion protein used in the in vitro RNA-binding studies performed by Donald and Jackson (5). Due to the difficulties in releasing ␥b from MBP, the uncleaved fusion protein was used in the zinc blotting experiments, and an MBP-lacZ fusion protein was used as a negative control to ensure that positive results were not attributable to the MBP.…”

Section: Species Of ␥B Corresponding To Sizes Expected For Monomers (mentioning

confidence: 99%

“…Furthermore, single-stranded RNA-binding activity has been demonstrated for a recombinant GST-␥b fusion protein in in vitro gel shift studies. Lysine and arginine residues within the BM were demonstrated to mediate this binding, whereas cysteine and histidine substitutions in the C1 and C2 regions had little effect on in vitro RNA-binding activity (5).…”

mentioning

confidence: 99%

“…Deletion of BSMV ␥b (5,21) and TRV p16 (18), both of which have RNA-binding activity, or PCV p15 (7) causes a dramatic decreases in viral RNA levels that can be rescued by supplying the appropriate CRP in trans. Furthermore, the TRV p16 protein can be functionally replaced by the BSMV ␥b, SBWMV p19, or Cucumber mosaic virus (CMV) 2b proteins, suggesting that these proteins may share some common biological functions (18).…”

mentioning

confidence: 99%

See 2 more Smart Citations

The N-Terminal 85 Amino Acids of the Barley Stripe Mosaic Virus γb Pathogenesis Protein Contain Three Zinc-Binding Motifs

Bragg

Lawrence

Jackson

2004

J Virol

View full text Add to dashboard Cite

Barley stripe mosaic virus RNA␥ encodes ␥b, a cysteine-rich protein that affects pathogenesis. Nine of the eleven cysteines are concentrated in two clusters, designated C1 (residues 1 to 23) and C2 (residues 60 to 85), that are arranged in zinc finger-like motifs. A basic motif (BM) rich in lysine and arginine (residues 19 to 47) resides between the C1 and C2 clusters. We have demonstrated that ␥b binds zinc and that the C1, BM, and C2 motifs have independent zinc-binding activities. To evaluate the requirements for binding, mutations were introduced into each region. Cysteine residues at positions 7, 9, 10, 19, and 23 in the C1 motif were replaced with serines. In the BM, asparagines were substituted for lysines at positions 26 and 35, glutamine for arginine at position 25, and glycines for arginines at positions 33 and 36. The C2 mutations included cysteine replacements with serines at positions 60, 64, 71, and 81, and a histidine-to-leucine change at position 85. These mutations destroyed zinc-binding activity in each of the isolated motifs. ␥b derivatives containing mutations in only two of the motifs retained the ability to bind zinc, whereas a ␥b derivative containing mutations inactivating all three motifs destroyed the ability to bind zinc. Plants inoculated with transcripts containing combinations of the C1, BM, and C2 mutations elicited a "null" phenotype in barley characteristic of ␥b deletion mutants and also delayed the appearance and reduced the size of local lesions in Chenopodium amaranticolor. These results show that zinc binding of each of the motifs is critical for the biological activity of ␥b.Barley stripe mosaic virus (BSMV) encodes a 17-kDa cysteine-rich protein (CRP) protein, designated ␥b, that is expressed from the 3Ј-proximal cistron of RNA␥ (Fig. 1A). The ␥b protein is expressed early and remains at elevated levels throughout the course of BSMV infection (6). Although ␥b is dispensable for both viral replication and movement in the ND18 strain of the virus, in the ␥⌬2.1 deletion mutant, which removes the bulk of the ␥b gene, symptom onset is delayed in barley, and symptoms are attenuated, resulting in a null phenotype characterized by an erratic mosaic pattern (21). Further analysis of this mutant suggests that ␥b has differential effects on RNA accumulation and protein expression and that it may regulate the synthesis of proteins encoded on RNA␤. Interestingly, in the type strain of BSMV, the ␥b protein is essential for systemic symptom development (21), and the requirement for ␥b is linked to a 372-nucleotide (nt) direct repeat in the 5Ј region of RNA␥ that overlaps the start codon and increases the size of the ␥a gene. This gene encodes the polymerase component of the viral replicase and therefore, this strain-specific difference suggests that subtle effects on replication contribute to the phenotypic effects of mutations in the ␥b protein.Nine of the eleven cysteine residues in the ␥b protein are concentrated in two clusters toward the N terminus of the protein. The C1 (amino acid...

show abstract

Plant–Virus Interactions: Defence and Counter‐Defence

Lewsey

Palukaitis²,

Carr

2018

Annual Plant Reviews Online

View full text Add to dashboard Cite

Viruses replicate in intimate association with their host cells. This has influenced the means by which plants defend themselves against viruses and the strategies adopted by viruses to exploit host plants. In this chapter, we examine howRgene‐mediated resistance against specific avirulent viral pathogens differs in important respects from resistance against non‐viral pathogens (bacteria, fungi, oomycetes, etc.) while utilising many of the same signal transduction pathways. We also explore mechanisms of recessive gene‐mediated resistance to viruses and genetically determined resistance to viral movement. Finally, we describe the emergence of host RNA silencing pathways as key determinants of the outcome of most plant–virus interactions. These pathways can act as important effectors of basal and induced resistance to viruses. Additionally, RNA silencing pathways can act as targets for viral suppressor proteins. Disruption of silencing pathways is the predominant means by which viruses induce disease symptoms in susceptible plant hosts.

show abstract

RNA-binding activities of barley stripe mosaic virus b fusion proteins

Cited by 45 publications

References 34 publications

Double-Stranded RNA Binding May Be a General Plant RNA Viral Strategy To Suppress RNA Silencing

Double-Stranded RNA Binding May Be a General Plant RNA Viral Strategy To Suppress RNA Silencing

The N-Terminal 85 Amino Acids of the Barley Stripe Mosaic Virus γb Pathogenesis Protein Contain Three Zinc-Binding Motifs

Plant–Virus Interactions: Defence and Counter‐Defence

Contact Info

Product

Resources

About