scholarly journals Multiple Cis-acting elements modulate programmed -1 ribosomal frameshifting in Pea enation mosaic virus

2015 ◽  
Vol 44 (2) ◽  
pp. 878-895 ◽  
Author(s):  
Feng Gao ◽  
Anne E. Simon
Keyword(s):  
Mosaic Virus ◽  
Order Structure ◽  
Wild Type ◽  
Long Distance ◽  
Ribosomal Frameshifting ◽  
Cis Acting ◽  
Alternative Conformation ◽  
Positive Strand Rna ◽  
Pea Enation Mosaic Virus ◽  
Lower Stem

Abstract Programmed -1 ribosomal frameshifting (-1 PRF) is used by many positive-strand RNA viruses for translation of required products. Despite extensive studies, it remains unresolved how cis-elements just downstream of the recoding site promote a precise level of frameshifting. The Umbravirus Pea enation mosaic virus RNA2 expresses its RNA polymerase by -1 PRF of the 5′-proximal ORF (p33). Three hairpins located in the vicinity of the recoding site are phylogenetically conserved among Umbraviruses. The central Recoding Stimulatory Element (RSE), located downstream of the p33 termination codon, is a large hairpin with two asymmetric internal loops. Mutational analyses revealed that sequences throughout the RSE and the RSE lower stem (LS) structure are important for frameshifting. SHAPE probing of mutants indicated the presence of higher order structure, and sequences in the LS may also adapt an alternative conformation. Long-distance pairing between the RSE and a 3′ terminal hairpin was less critical when the LS structure was stabilized. A basal level of frameshifting occurring in the absence of the RSE increases to 72% of wild-type when a hairpin upstream of the slippery site is also deleted. These results suggest that suppression of frameshifting may be needed in the absence of an active RSE conformation.

scholarly journals Components of Arabidopsis Defense- and Ethylene-Signaling Pathways Regulate Susceptibility to Cauliflower mosaic virus by Restricting Long-Distance Movement

2007 ◽  
Vol 20 (6) ◽  
pp. 659-670 ◽  
Author(s):  
Andrew J. Love ◽  
Valérie Laval ◽  
Chiara Geri ◽  
Janet Laird ◽  
A. Deri Tomos ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Systemic Acquired Resistance ◽  
Fluorescent Protein ◽  
Acquired Resistance ◽  
Systemic Infection ◽  
Cauliflower Mosaic Virus ◽  
Virus Movement ◽  
Wild Type ◽  
Long Distance ◽  
Systemic Spread

We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling to infection by Cauliflower mosaic virus (CaMV). Mutants cpr1-1 and cpr5-2, in which SA-dependent defense signaling is activated constitutively, were substantially more resistant than the wild type to systemic infection, implicating SA signaling in defense against CaMV. However, SA-deficient NahG, sid2-2, eds5-1, and pad4-1 did not show enhanced susceptibility. A cpr5 eds5 double mutant also was resistant, suggesting that resistance in cpr5 may function partially independently of SA. Treatment of cpr5 and cpr5 eds5, but not cpr1, with salicyl-hydroxamic acid, an inhibitor of alternative oxidase, partially restored susceptibility to wild-type levels. Mutants etr1-1, etr1-3, and ein2-1, and two mutants with lesions in ET/JA-mediated defense, eds4 and eds8, also showed reduced virus susceptibility, demonstrating that ET-dependent responses also play a role in susceptibility. We used a green fluorescent protein (GFP)-expressing CaMV recombinant to monitor virus movement. In mutants with reduced susceptibility, cpr1-1, cpr5-2, and etr1-1, CaMV-GFP formed local lesions similar to the wild type, but systemic spread was almost completely absent in cpr1 and cpr5 and was substantially reduced in etr1-1. Thus, mutations with enhanced systemic acquired resistance or compromised ET signaling show diminished long-distance virus movement.

scholarly journals Mutation of Host dnaJ Homolog Inhibits Brome Mosaic Virus Negative-Strand RNA Synthesis

2003 ◽  
Vol 77 (5) ◽  
pp. 2990-2997 ◽  
Author(s):  
Yuriko Tomita ◽  
Tomomitsu Mizuno ◽  
Juana Díez ◽  
Satoshi Naito ◽  
Paul Ahlquist ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Synthesis ◽  
Brome Mosaic Virus ◽  
Wild Type ◽  
Positive Strand ◽  
Replication Complex ◽  
Negative Strand ◽  
Rna Accumulation ◽  
Positive Strand Rna ◽  
Mutant Cells

ABSTRACT The replication of positive-strand RNA viruses involves not only viral proteins but also multiple cellular proteins and intracellular membranes. In both plant cells and the yeast Saccharomyces cerevisiae, brome mosaic virus (BMV), a member of the alphavirus-like superfamily, replicates its RNA in endoplasmic reticulum (ER)-associated complexes containing viral 1a and 2a proteins. Prior to negative-strand RNA synthesis, 1a localizes to ER membranes and recruits both positive-strand BMV RNA templates and the polymerase-like 2a protein to ER membranes. Here, we show that BMV RNA replication in S. cerevisiae is markedly inhibited by a mutation in the host YDJ1 gene, which encodes a chaperone Ydj1p related to Escherichia coli DnaJ. In the ydj1 mutant, negative-strand RNA accumulation was inhibited even though 1a protein associated with membranes and the positive-strand RNA3 replication template and 2a protein were recruited to membranes as in wild-type cells. In addition, we found that in ydj1 mutant cells but not wild-type cells, a fraction of 2a protein accumulated in a membrane-free but insoluble, rapidly sedimenting form. These and other results show that Ydj1p is involved in forming BMV replication complexes active in negative-strand RNA synthesis and suggest that a chaperone system involving Ydj1p participates in 2a protein folding or assembly into the active replication complex.

scholarly journals In Vivo Packaging of Brome Mosaic Virus RNA3, but Not RNAs 1 and 2, Is Dependent on a cis-Acting 3′ tRNA-Like Structure

2006 ◽  
Vol 81 (1) ◽  
pp. 173-181 ◽  
Author(s):  
Padmanaban Annamalai ◽  
A. L. N. Rao
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Nicotiana Benthamiana ◽  
Untranslated Region ◽  
Northern Blot Analysis ◽  
Brome Mosaic Virus ◽  
Wild Type ◽  
Cis Acting

ABSTRACT The four encapsidated RNAs of brome mosaic virus (BMV; B1, B2, B3, and B4) contain a highly conserved 3′ 200-nucleotide (nt) region encompassing the tRNA-like structure (TLS) which is required for packaging in vitro (Y. G. Choi, T. W. Dreher, and A. L. N. Rao, Proc. Natl. Acad. Sci. USA 99:655-660, 2002). To validate these observations in vivo, we performed packaging assays using Agrobacterium-mediated transient expression of RNAs and coat protein (CP) (P. Annamalai and A. L. N. Rao, Virology 338:96-111, 2005). Coexpression of TLS-less constructs of B1 or B2 or B3 and CP mRNAs in Nicotiana benthamiana leaves resulted in packaging of TLS-less B1 and B2 but not B3, suggesting that packaging of B3 requires the TLS in cis. This conjecture was confirmed by the efficient packaging of a B3 chimera in which the viral TLS was replaced with a cellular tRNATyr. When N. benthamiana leaves were infiltrated with a mixture of transformants containing wild-type B1 (wtB1) plus wtB2 plus a TLS-less B3 (wtB1+wtB2+TLS-lessB3), the 3′ end of progeny B3 was restored by heterologous recombination with that of either B1 or B2. This intrinsic cis-requirement of TLS in promoting B3 packaging was further confirmed when a mixture containing agrotransformants of TLS-less B1+B2+B3 was supplemented with either wtB4 or a 3′ 200-nt or 3′ 336-nt untranslated region (UTR) of B3. Northern blot analysis followed by sequencing of B3 progeny revealed that replication of TLS-less B3, but not TLS-less B1 or B2, was fully restored due to recombination with TLS from transiently expressed wtB4 or the B3 3′ UTR. Collectively, these observations suggested that the requirement of a cis-acting TLS is distinct for B3 compared with B1 or B2.

scholarly journals Sequence-, Tissue-, and Delivery-Specific Targeting of RNA During Post-Transcriptional Gene Silencing

2002 ◽  
Vol 15 (8) ◽  
pp. 753-763 ◽  
Author(s):  
Ezequiel Balmori-Melian ◽  
Robin M. MacDiarmid ◽  
David L. Beck ◽  
Richard C. Gardner ◽  
Richard L. S. Forster
Keyword(s):  
Gene Silencing ◽  
Mosaic Virus ◽  
Viral Vectors ◽  
Transcriptional Gene Silencing ◽  
Wild Type ◽  
Long Distance ◽  
Post Transcriptional Gene Silencing ◽  
In The Wild ◽  
Long Distance Movement ◽  
White Clover Mosaic Virus

Transgenic Nicotiana benthamiana plants expressing an untranslatable version of the coat protein (CP) gene from the Tamarillo mosaic virus (TaMV) were either resistant to TaMV infection or recovered from infection. These phenotypes were the result of a post-transcriptional gene silencing (PTGS) mechanism that targeted TaMV-CP sequences for degradation. The TaMV-CP sequences were degraded when present in the wild-type TaMV potyvirus, in transgene mRNA, or in chimeric viral vectors based on White clover mosaic virus. The more efficiently targeted region was mapped to a 134-nt segment. Differences were observed in the efficiency of targeting during cell-to-cell and long-distance movement of the chimeric viruses. However, the TaMV-CP sequences do not appear to be targeted for degradation when delivered by biolistics.

scholarly journals The Multifunctional Long-Distance Movement Protein of Pea Enation Mosaic Virus 2 Protects Viral and Host Transcripts from Nonsense-Mediated Decay

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Jared P. May ◽  
Philip Z. Johnson ◽  
Muhammad Ilyas ◽  
Feng Gao ◽  
Anne E. Simon
Keyword(s):  
Mosaic Virus ◽  
Rna Viruses ◽  
Rna Virus ◽  
Messenger Rnas ◽  
Rna Seq ◽  
Long Distance ◽  
Content Type ◽  
Nonsense Mediated Decay ◽  
Long Distance Movement ◽  
Pea Enation Mosaic Virus

ABSTRACT The nonsense-mediated decay (NMD) pathway presents a challenge for RNA viruses with termination codons that precede extended 3′ untranslated regions (UTRs). The umbravirus Pea enation mosaic virus 2 (PEMV2) is a nonsegmented, positive-sense RNA virus with an unusually long 3′ UTR that is susceptible to NMD. To establish a systemic infection, the PEMV2 long-distance movement protein p26 was previously shown to both stabilize viral RNAs and bind them for transport through the plant’s vascular system. The current study demonstrated that p26 protects both viral and nonviral messenger RNAs from NMD. Although p26 localizes to both the cytoplasm and nucleolus, p26 exerts its anti-NMD effects exclusively in the cytoplasm independently of long-distance movement. Using a transcriptome-wide approach in the model plant Nicotiana benthamiana, p26 protected a subset of cellular NMD target transcripts, particularly those containing long, structured, GC-rich 3′ UTRs. Furthermore, transcriptome sequencing (RNA-seq) revealed that the NMD pathway is highly dysfunctional during PEMV2 infection, with 1,820 (48%) of NMD targets increasing in abundance. Widespread changes in the host transcriptome are common during plant RNA virus infections, and these results suggest that, in at least some instances, virus-mediated NMD inhibition may be a major contributing factor. IMPORTANCE Nonsense-mediated decay (NMD) represents an RNA regulatory pathway that degrades both natural and faulty messenger RNAs with long 3′ untranslated regions. NMD targets diverse families of RNA viruses, requiring that viruses counteract the NMD pathway for successful amplification in host cells. A protein required for long-distance movement of Pea enation mosaic virus 2 (PEMV2) is shown to also protect both viral and host mRNAs from NMD. RNA-seq analyses of the Nicotiana benthamiana transcriptome revealed that PEMV2 infection significantly impairs the host NMD pathway. RNA viruses routinely induce large-scale changes in host gene expression, and, like PEMV2, may use NMD inhibition to alter the host transcriptome in an effort to increase virus amplification.

scholarly journals Cucumber mosaic virus-Plant Interactions: Identification of 3a Protein Sequences Affecting Infectivity, Cell-to-Cell Movement, and Long-distance Movement

2001 ◽  
Vol 14 (3) ◽  
pp. 378-385 ◽  
Author(s):  
Qiubo Li ◽  
Ki Hyun Ryu ◽  
Peter Palukaitis
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Movement ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Plant Interactions ◽  
Wild Type ◽  
Long Distance ◽  
In Trans ◽  
Long Distance Movement

Mutants of the Cucumber mosaic virus (CMV) movement protein (MP) were generated and analyzed for their effects on virus movement and pathogenicity in vivo. Similar to the wild-type MP, mutants M1, M2, and M3, promoted virus movement in eight plant species. Mutant M3 showed some differences in pathogenicity in one host species. Mutant M8 showed some host-specific alterations in movement in two hypersensitive hosts of CMV. Mutant M9 showed altered pathogenicity on three hosts and was temperature sensitive for long-distance movement, demonstrating that cell-to-cell and long-distance movement are distinct movement functions for CMV. Four mutants (M4, M5, M6, and M7) were debilitated from movement in all hosts tested. Mutants M4, M5, and M6 could be complemented in trans by the wild-type MP expressed transgenically, although not by each other or by mutant M9 (at the restrictive temperature). Mutant M7 showed an inability to be complemented in trans. From these mutants, different aspects of the CMV movement process could be defined and specific roles for particular sequence domains assigned. The broader implications of these functions are discussed.

scholarly journals The C terminus of the movement protein of Brome mosaic virus controls the requirement for coat protein in cell-to-cell movement and plays a role in long-distance movement

2004 ◽  
Vol 85 (6) ◽  
pp. 1751-1761 ◽  
Author(s):  
Atsushi Takeda ◽  
Masanori Kaido ◽  
Tetsuro Okuno ◽  
Kazuyuki Mise
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Brome Mosaic Virus ◽  
Wild Type ◽  
Long Distance ◽  
C Terminus ◽  
Mouth Disease Virus ◽  
Long Distance Movement

The 3a movement protein (MP) plays a central role in the movement of Brome mosaic virus (BMV). To identify the functional regions in BMV MP, 24 alanine-scanning (AS) MP mutants of BMV were constructed. Infectivity of the AS mutants in the host plant Chenopodium quinoa showed that the central region of BMV MP is important for viral movement and both termini of BMV MP have effects on the development of systemic symptoms. A green-fluorescent-protein-expressing RNA3-based BMV vector containing a 2A sequence from Foot-and-mouth disease virus was also constructed. Using this vector, two AS mutants that showed more efficient cell-to-cell movement than wild-type BMV were identified. The MPs of these two AS mutants, which have mutations at their C termini, mediated cell-to-cell movement independently of coat protein (CP), unlike wild-type BMV MP. Furthermore, a BMV mutant with a truncation in the C-terminal 42 amino acids of MP was also able to move from cell to cell without CP, but did not move systemically, even in the presence of CP. These results and an encapsidation analysis suggest that the C terminus of BMV MP is involved in the requirement for CP in cell-to-cell movement and plays a role in long-distance movement. Furthermore, the ability to spread locally and form virions is not sufficient for the long-distance movement of BMV. The roles of MP and CP in BMV movement are discussed.

scholarly journals Maize resistance to Sugarcane mosaic virus

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 542-544
Author(s):  
R. Pokorný ◽  
M. Porubová
Keyword(s):  
Mosaic Virus ◽  
Systemic Infection ◽  
Sugarcane Mosaic Virus ◽  
Resistant Line ◽  
Mechanisms Of Resistance ◽  
Long Distance ◽  
Maize Hybrids ◽  
Resistant Lines ◽  
Maize Resistance ◽  
Long Distance Movement

Under greenhouse conditions 12 maize hybrids derived from crosses of four resistant lines with several lines of different level of susceptibility were evaluated for resistance to Czech isolate of Sugarcane mosaic virus (SCMV). These hybrids were not fully resistant to isolate of SCMV, but the symptoms on their newly growing leaves usually developed 1 to 3 weeks later in comparison with particular susceptible line, the course of infection was significantly slower and rate of infection lower. As for mechanisms of resistance, the presence of SCMV was detected by ELISA in inoculated leaves both of resistant and susceptible lines, but virus was detected 7 days later in resistant line. Systemic infection developed only in susceptible lines. These results indicate restriction of viral long distance movement in the resistant line.

scholarly journals Rootstocks Overexpressing StNPR1 and StDREB1 Improve Osmotic Stress Tolerance of Wild-Type Scion in Transgrafted Tobacco Plants

2021 ◽  
Vol 22 (16) ◽  
pp. 8398
Author(s):  
Yasmine S. Hezema ◽  
Mukund R. Shukla ◽  
Alok Goel ◽  
Murali M. Ayyanath ◽  
Sherif M. Sherif ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Transgenic Tobacco ◽  
Physiological Status ◽  
Wild Type ◽  
Long Distance ◽  
Graft Union ◽  
Tobacco Plants ◽  
Osmotic Stress Tolerance ◽  
And Function ◽  
Gene Expression Levels

In grafted plants, the movement of long-distance signals from rootstocks can modulate the development and function of the scion. To understand the mechanisms by which tolerant rootstocks improve scion responses to osmotic stress (OS) conditions, mRNA transport of osmotic responsive genes (ORGs) was evaluated in a tomato/potato heterograft system. In this system, Solanum tuberosum was used as a rootstock and Solanum lycopersicum as a scion. We detected changes in the gene expression levels of 13 out of the 21 ORGs tested in the osmotically stressed plants; of these, only NPR1 transcripts were transported across the graft union under both normal and OS conditions. Importantly, OS increased the abundance of StNPR1 transcripts in the tomato scion. To examine mRNA mobility in transgrafted plants, StNPR1 and StDREB1 genes representing the mobile and non-mobile transcripts, respectively, were overexpressed in tobacco (Nicotiana tabacum). The evaluation of transgenic tobacco plants indicated that overexpression of these genes enhanced the growth and improved the physiological status of transgenic plants growing under OS conditions induced by NaCl, mannitol and polyethylene glycol (PEG). We also found that transgenic tobacco rootstocks increased the OS tolerance of the WT-scion. Indeed, WT scions on transgenic rootstocks had higher ORGs transcript levels than their counterparts on non-transgenic rootstocks. However, neither StNPR1 nor StDREB1 transcripts were transported from the transgenic rootstock to the wild-type (WT) tobacco scion, suggesting that other long-distance signals downstream these transgenes could have moved across the graft union leading to OS tolerance. Overall, our results signify the importance of StNPR1 and StDREB1 as two anticipated candidates for the development of stress-resilient crops through transgrafting technology.

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