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Chattopadhyay A, Abdul Kader Jailani A, Roy A, Mukherjee SK, Mandal B. Prediction of putative regulatory elements in the subgenomic promoters of cucumber green mottle mosaic virus and their interactions with the RNA dependent RNA polymerase domain. Virusdisease 2020; 31:503-516. [PMID: 33381623 DOI: 10.1007/s13337-020-00640-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 10/27/2020] [Indexed: 11/26/2022] Open
Abstract
Characterization of the subgenomic RNA (sgRNA) promoter of many plant viruses is important to understand the expression of downstream genes and also to configure their genome into a suitable virus gene-vector system. Cucumber green mottle mosaic virus (CGMMV, genus Tobamovirus) is one of the RNA viruses, which is extensively being exploited as the suitable gene silencing and protein expression vector. Even though, characters of the sgRNA promoters (SGPs) of CGMMV are yet to be addressed. In the present study, we predicted the SGP for the movement protein (MP) and coat protein (CP) of CGMMV. Further, we identified the key regulatory elements in the SGP regions of MP and CP, and their interactions with the core RNA dependent RNA polymerase (RdRp) domain of CGMMV was deciphered. The modeled structure of core RdRp contains two palm (1-41 aa, and 63-109 aa), one finger (42-62 aa) subdomains with three conserved RdRp motifs that played important role in binding to the SGP nucleic acids. RdRp strongly preferred the double helix form of the stem region in the stem and loop (SL) structures, and the internal bulge elements. In MP-SGP, a total of six elements was identified; of them, the affinity of binding to - 26 nt to - 17 nt site (CGCGGAAAAG) was higher through the formation of strong hydrogen bonds with LYS16, TYR17, LYS19, SER20, etc. of the motif A in the palm subdomain of RdRp. Similar strong interactions were noticed in the internal bulge (CAACUUU) located at + 33 to + 39 nt adjacent to the translation start site (TLSS) (+ 1). These could be proposed as the putative core promoter elements in MP-SGP. Likewise, total five elements were predicted within - 114 nt to + 144 nt region of CP-SGP with respect to CP-TLSS. Of them, RdRp preferred to bind at the small hairpin located at - 60 nt to - 43 nt (UUGGAGGUUUAGCCUCCA) in the upstream region, and at the complex duplex structure spanning between + 99 and + 114 nt in the downstream region, thus indicating the distribution of core promoter within - 60 nt to + 114 nt region of CP-SGP with respect to TLSS (+ 1) of the CP; whereas, the - 114 nt to + 144 nt region of CP-SGP might be necessary for the full activity of the CP-SGP. Our in silico prediction certifies the gravity of these nucleotide stretches as the RNA regulatory elements and identifies their potentiality for binding with of palm and finger sub-domain of RdRp. Identification of such elements will be helpful to anticipate the critical length of the SGPs. Our finding will not only be helpful to delineate the SGPs of CGMMV but also their subsequent application in the efficient construction of virus gene-vector for the expression of foreign protein in plant.
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Affiliation(s)
- Anirudha Chattopadhyay
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
| | - A Abdul Kader Jailani
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Anirban Roy
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Sunil Kumar Mukherjee
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Bikash Mandal
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
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Shrestha N, Bujarski JJ. Long Noncoding RNAs in Plant Viroids and Viruses: A Review. Pathogens 2020; 9:E765. [PMID: 32961969 PMCID: PMC7559573 DOI: 10.3390/pathogens9090765] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 12/11/2022] Open
Abstract
Infectious long-noncoding (lnc) RNAs related to plants can be of both viral and non-viral origin. Viroids are infectious plant lncRNAs that are not related to viruses and carry the circular, single-stranded, non-coding RNAs that replicate with host enzymatic activities via a rolling circle mechanism. Viroids interact with host processes in complex ways, emerging as one of the most productive tools for studying the functions of lncRNAs. Defective (D) RNAs, another category of lnc RNAs, are found in a variety of plant RNA viruses, most of which are noncoding. These are derived from and are replicated by the helper virus. D RNA-virus interactions evolve into mutually beneficial combinations, enhancing virus fitness via competitive advantages of moderated symptoms. Yet the satellite RNAs are single-stranded and include either large linear protein-coding ss RNAs, small linear ss RNAs, or small circular ss RNAs (virusoids). The satellite RNAs lack sequence homology to the helper virus, but unlike viroids need a helper virus to replicate and encapsidate. They can attenuate symptoms via RNA silencing and enhancement of host defense, but some can be lethal as RNA silencing suppressor antagonists. Moreover, selected viruses produce lncRNAs by incomplete degradation of genomic RNAs. They do not replicate but may impact viral infection, gene regulation, and cellular functions. Finally, the host plant lncRNAs can also contribute during plant-virus interactions, inducing plant defense and the regulation of gene expression, often in conjunction with micro and/or circRNAs.
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Affiliation(s)
- Nipin Shrestha
- Department of Biological Sciences and Plant Molecular and Bioinformatics Center, Northern Illinois University, DeKalb, IL 60115, USA
| | - Józef J. Bujarski
- Department of Biological Sciences and Plant Molecular and Bioinformatics Center, Northern Illinois University, DeKalb, IL 60115, USA
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Strugała A, Bierwagen P, Rybka J, Giersig M, Figlerowicz M, Urbanowicz A. BMV Propagation, Extraction and Purification Using Chromatographic Methods. Bio Protoc 2018; 8:e2935. [DOI: 10.21769/bioprotoc.2935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/06/2018] [Accepted: 07/26/2018] [Indexed: 11/02/2022] Open
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Biophysical analysis of BMV virions purified using a novel method. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1068-1069:157-163. [PMID: 29069631 DOI: 10.1016/j.jchromb.2017.10.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/03/2017] [Accepted: 10/09/2017] [Indexed: 01/12/2023]
Abstract
Brome mosaic virus (BMV) has been successfully loaded with different types of nanoparticles. However, studies concerning its application as a nanoparticle carrier demand high-purity virions in large amounts. Existing BMV purification protocols rely on multiple differential ultracentrifugation runs of the initially purified viral preparation. Herein, we describe an alternative method for BMV purification based on ion-exchange chromatography and size-exclusion chromatography (SEC) yielding 0.2mg of virus from 1g of plant tissue. Our method is of similar efficiency to previously described protocols and can easily be scaled up. The method results in high-quality BMV preparations as confirmed by biophysical analyses, including cryogenic transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), static light scattering (SLS), and circular dichroism (CD) measurements and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy. Our results revealed that purified BMV capsids are stable and monodisperse and can be used for further downstream applications. In this work, we also characterize secondary structure and size fluctuations of the BMV virion at different pH values.
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Newburn LR, White KA. Cis-acting RNA elements in positive-strand RNA plant virus genomes. Virology 2015; 479-480:434-43. [PMID: 25759098 DOI: 10.1016/j.virol.2015.02.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/19/2015] [Accepted: 02/17/2015] [Indexed: 11/25/2022]
Abstract
Positive-strand RNA viruses are the most common type of plant virus. Many aspects of the reproductive cycle of this group of viruses have been studied over the years and this has led to the accumulation of a significant amount of insightful information. In particular, the identification and characterization of cis-acting RNA elements within these viral genomes have revealed important roles in many fundamental viral processes such as virus disassembly, translation, genome replication, subgenomic mRNA transcription, and packaging. These functional cis-acting RNA elements include primary sequences, secondary and tertiary structures, as well as long-range RNA-RNA interactions, and they typically function by interacting with viral or host proteins. This review provides a general overview and update on some of the many roles played by cis-acting RNA elements in positive-strand RNA plant viruses.
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Affiliation(s)
- Laura R Newburn
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - K Andrew White
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
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The tripartite virions of the brome mosaic virus have distinct physical properties that affect the timing of the infection process. J Virol 2014; 88:6483-91. [PMID: 24672042 DOI: 10.1128/jvi.00377-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The three subsets of virions that comprise the Brome mosaic virus (BMV) were previously thought to be indistinguishable. This work tested the hypothesis that distinct capsid-RNA interactions in the BMV virions allow different rates of viral RNA release. Several results support distinct interactions between the capsid and the BMV genomic RNAs. First, the deletion of the first eight residues of the BMV coat protein (CP) resulted in the RNA1-containing particles having altered morphologies, while those containing RNA2 were unaffected. Second, subsets of the BMV particles separated by density gradients into a pool enriched for RNA1 (B1) and for RNA2 and RNA3/4 (B2.3/4) were found to have different physiochemical properties. Compared to the B2.3/4 particles, the B1 particles were more sensitive to protease digestion and had greater resistivity to nanoindentation by atomic force microscopy and increased susceptibility to nuclease digestion. Mapping studies showed that portions of the arginine-rich N-terminal tail of the CP could interact with RNA1. Mutational analysis in the putative RNA1-contacting residues severely reduced encapsidation of BMV RNA1 without affecting the encapsidation of RNA2. Finally, during infection of plants, the more easily released RNA1 accumulated to higher levels early in the infection. IMPORTANCE Viruses with genomes packaged in distinct virions could theoretically release the genomes at different times to regulate the timing of gene expression. Using an RNA virus composed of three particles, we demonstrated that the RNA in one of the virions is released more easily than the other two in vitro. The differential RNA release is due to distinct interactions between the viral capsid protein and the RNAs. The ease of RNA release is also correlated with the more rapid accumulation of that RNA in infected plants. Our study identified a novel role for capsid-RNA interactions in the regulation of a viral infection.
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Ni P, Vaughan RC, Tragesser B, Hoover H, Kao CC. The plant host can affect the encapsidation of brome mosaic virus (BMV) RNA: BMV virions are surprisingly heterogeneous. J Mol Biol 2014; 426:1061-76. [PMID: 24036424 PMCID: PMC3944473 DOI: 10.1016/j.jmb.2013.09.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/02/2013] [Accepted: 09/08/2013] [Indexed: 01/05/2023]
Abstract
Brome mosaic virus (BMV) packages its genomic and subgenomic RNAs into three separate viral particles. BMV purified from barley, wheat, and tobacco have distinct relative abundances of the encapsidated RNAs. We seek to identify the basis for the host-dependent differences in viral RNA encapsidation. Sequencing of the viral RNAs revealed recombination events in the 3' untranslated region of RNA1 of BMV purified from barley and wheat, but not from tobacco. However, the relative amounts of the BMV RNAs that accumulated in barley and wheat are similar and RNA accumulation is not sufficient to account for the difference in RNA encapsidation. Virions purified from barley and wheat were found to differ in their isoelectric points, resistance to proteolysis, and contacts between the capsid residues and the RNA. Mass spectrometric analyses revealed that virions from the three hosts had different post-translational modifications that should impact the physiochemical properties of the virions. Another major source of variation in RNA encapsidation was due to the purification of BMV particles to homogeneity. Highly enriched BMV present in lysates had a surprising range of sizes, buoyant densities, and distinct relative amounts of encapsidated RNAs. These results show that the encapsidated BMV RNAs reflect a combination of host effects on the physiochemical properties of the viral capsids and the enrichment of a subset of virions. The previously unexpected heterogeneity in BMV should influence the timing of the infection and also the host innate immune responses.
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Affiliation(s)
- Peng Ni
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Robert C Vaughan
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Brady Tragesser
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Haley Hoover
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - C Cheng Kao
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
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Sztuba-Solińska J, Fanning SW, Horn JR, Bujarski JJ. Mutations in the coat protein-binding cis-acting RNA motifs debilitate RNA recombination of Brome mosaic virus. Virus Res 2012; 170:138-49. [PMID: 23079110 PMCID: PMC7114393 DOI: 10.1016/j.virusres.2012.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/04/2012] [Accepted: 10/05/2012] [Indexed: 12/14/2022]
Abstract
We have previously described the efficient homologous recombination system between 5' subgenomic RNA3a (sgRNA3a) and genomic RNA3 of Brome mosaic virus (BMV) in barley protoplasts (Sztuba-Solińska et al., 2011a). Here, we demonstrated that sequence alterations in the coat protein (CP)-binding cis-acting RNA motifs, the Bbox region (in the intercistronic RNA3 sequence) and the RNA3 packaging element (PE, in the movement protein ORF), reduced crossover frequencies in protoplasts. Additionally, the modification of Bbox-like element in the 5' UTR region strongly debilitated crossovers. Along the lines of these observations, RNA3 mutants not expressing CP or expressing mutated CPs also reduced recombination. A series of reciprocal transfections demonstrated a functional crosstalk between the Bbox and PE elements. Altogether, our data imply the role of CP in sgRNA3a-directed recombination by either facilitating the interaction of the RNA substrates and/or by creating roadblocks for the viral replicase.
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Affiliation(s)
- Joanna Sztuba-Solińska
- Plant Molecular Biology Center and the Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
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Sztuba-Solińska J, Stollar V, Bujarski JJ. Subgenomic messenger RNAs: mastering regulation of (+)-strand RNA virus life cycle. Virology 2011; 412:245-55. [PMID: 21377709 PMCID: PMC7111999 DOI: 10.1016/j.virol.2011.02.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/14/2010] [Accepted: 02/04/2011] [Indexed: 12/12/2022]
Abstract
Many (+)-strand RNA viruses use subgenomic (SG) RNAs as messengers for protein expression, or to regulate their viral life cycle. Three different mechanisms have been described for the synthesis of SG RNAs. The first mechanism involves internal initiation on a (−)-strand RNA template and requires an internal SGP promoter. The second mechanism makes a prematurely terminated (−)-strand RNA which is used as template to make the SG RNA. The third mechanism uses discontinuous RNA synthesis while making the (−)-strand RNA templates. Most SG RNAs are translated into structural proteins or proteins related to pathogenesis: however other SG RNAs regulate the transition between translation and replication, function as riboregulators of replication or translation, or support RNA–RNA recombination. In this review we discuss these functions of SG RNAs and how they influence viral replication, translation and recombination.
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Affiliation(s)
- Joanna Sztuba-Solińska
- Plant Molecular Biology Center and the Department of Biological Sciences, Northern Illinois University, De Kalb, IL 60115, USA
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Sztuba-Solińska J, Urbanowicz A, Figlerowicz M, Bujarski JJ. RNA-RNA recombination in plant virus replication and evolution. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:415-43. [PMID: 21529157 DOI: 10.1146/annurev-phyto-072910-095351] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
RNA-RNA recombination is one of the strongest forces shaping the genomes of plant RNA viruses. The detection of recombination is a challenging task that prompted the development of both in vitro and in vivo experimental systems. In the divided genome of Brome mosaic virus system, both inter- and intrasegmental crossovers are described. Other systems utilize satellite or defective interfering RNAs (DI-RNAs) of Turnip crinkle virus, Tomato bushy stunt virus, Cucumber necrosis virus, and Potato virus X. These assays identified the mechanistic details of the recombination process, revealing the role of RNA structure and proteins in the replicase-mediated copy-choice mechanism. In copy choice, the polymerase and the nascent RNA chain from which it is synthesized switch from one RNA template to another. RNA recombination was found to mediate the rearrangement of viral genes, the repair of deleterious mutations, and the acquisition of nonself sequences influencing the phylogenetics of viral taxa. The evidence for recombination, not only between related viruses but also among distantly related viruses, and even with host RNAs, suggests that plant viruses unabashedly test recombination with any genetic material at hand.
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Affiliation(s)
- Joanna Sztuba-Solińska
- Plant Molecular Biology Center, Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115, USA
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Recombination of 5' subgenomic RNA3a with genomic RNA3 of Brome mosaic bromovirus in vitro and in vivo. Virology 2010; 410:129-41. [PMID: 21111438 PMCID: PMC7111948 DOI: 10.1016/j.virol.2010.10.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/28/2010] [Accepted: 10/29/2010] [Indexed: 01/03/2023]
Abstract
RNA-RNA recombination salvages viral RNAs and contributes to their genomic variability. A recombinationally-active subgenomic promoter (sgp) has been mapped in Brome mosaic bromovirus (BMV) RNA3 (Wierzchoslawski et al., 2004. J. Virol.78, 8552-8864) and mRNA-like 5' sgRNA3a was characterized (Wierzchoslawski et al., 2006. J. Virol. 80, 12357-12366). In this paper we describe sgRNA3a-mediated recombination in both in vitro and in vivo experiments. BMV replicase-directed co-copying of (-) RNA3 with wt sgRNA3a generated RNA3 recombinants in vitro, but it failed to when 3'-truncated sgRNA3a was substituted, demonstrating a role for the 3' polyA tail. Barley protoplast co-transfections revealed that (i) wt sgRNA3a recombines at the 3' and the internal sites; (ii) 3'-truncated sgRNA3as recombine more upstream; and (iii) 5'-truncated sgRNA3 recombine at a low rate. In planta co-inoculations confirmed the RNA3-sgRNA3a crossovers. In summary, the non-replicating sgRNA3a recombines with replicating RNA3, most likely via primer extension and/or internal template switching.
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Yi G, Letteney E, Kim CH, Kao CC. Brome mosaic virus capsid protein regulates accumulation of viral replication proteins by binding to the replicase assembly RNA element. RNA (NEW YORK, N.Y.) 2009; 15:615-26. [PMID: 19237464 PMCID: PMC2661835 DOI: 10.1261/rna.1375509] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 01/16/2009] [Indexed: 05/20/2023]
Abstract
Viruses provide valuable insights into the regulation of molecular processes. Brome mosaic virus (BMV) is one of the simplest entities with four viral proteins and three genomic RNAs. Here we report that the BMV capsid protein (CP), which functions in RNA encapsidation and virus trafficking, also represses viral RNA replication in a concentration-dependent manner by inhibiting the accumulation of the RNA replication proteins. Expression of the replication protein 2a in trans can partially rescue BMV RNA accumulation. A mutation in the CP can decrease the repression of translation. Translation repression by the CP requires a hairpin RNA motif named the B Box that contains seven loop nucleotides (nt) within the 5' untranslated regions (UTR) of BMV RNA1 and RNA2. Purified CP can bind directly to the B Box RNA with a K (d) of 450 nM. The secondary structure of the B Box RNA was determined to contain a highly flexible 7-nt loop using NMR spectroscopy, native gel analysis, and thermal denaturation studies. The B Box is also recognized by the BMV 1a protein to assemble the BMV replicase, suggesting that the BMV CP can act to regulate several viral infection processes.
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Affiliation(s)
- Guanghui Yi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, 77843, USA
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Characterization of the 5'- and 3'-terminal subgenomic RNAs produced by a capillovirus: Evidence for a CP subgenomic RNA. Virology 2009; 385:521-8. [PMID: 19155038 DOI: 10.1016/j.virol.2008.12.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 12/11/2008] [Accepted: 12/16/2008] [Indexed: 11/20/2022]
Abstract
The members of Capillovirus genus encode two overlapping open reading frames (ORFs): ORF1 encodes a large polyprotein containing the replication-associated proteins plus a coat protein (CP), and ORF2 encodes a movement protein (MP), located within ORF1 in a different reading frame. Organization of the CP sequence as part of the replicase ORF is unusual in capilloviruses. In this study, we examined the capillovirus genome expression strategy by characterizing viral RNAs produced by Citrus tatter leaf virus (CTLV), isolate ML, a Capillovirus. CTLV-ML produced a genome-length RNA of approximately 6.5-kb and two 3'-terminal sgRNAs in infected tissue that contain the MP and CP coding sequences (3'-sgRNA1), and the CP coding sequence (3'-sgRNA2), respectively. Both 3'-sgRNAs initiate at a conserved octanucleotide (UUGAAAGA), and are 1826 (3'-sgRNA1) and 869 (3'-sgRNA2) nts with 119 and 15 nt leader sequences, respectively, suggesting that these two 3'-sgRNAs could serve to express the MP and CP. Additionally, accumulation of two 5'-terminal sgRNAs of 5586 (5'-sgRNA1) and 4625 (5'-sgRNA2) nts was observed, and their 3'-termini mapped to 38-44 nts upstream of the transcription start sites of 3'-sgRNAs. The presence of a separate 3'-sgRNA corresponding to the CP coding sequence and its cognate 5'-terminal sgRNA (5'-sgRNA1) suggests that CTLV-ML produces a dedicated sg mRNA for the expression of its CP.
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Sztuba-Solinska J, Bujarski JJ. Insights into the single-cell reproduction cycle of members of the family Bromoviridae: lessons from the use of protoplast systems. J Virol 2008; 82:10330-40. [PMID: 18684833 PMCID: PMC2573203 DOI: 10.1128/jvi.00746-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Joanna Sztuba-Solinska
- Department of Biological Sciences, Plant Molecular Biology Center, Montgomery Hall, Northern Illinois University, De Kalb, IL 60115, USA
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Abstract
Genetic recombination of viruses is a commonly found phenomenon in both DNA and RNA viruses. By exchanging of fragments of genetic material viruses gain important means leading to both variability and also to the repair of their genome. Biochemically, the processes of DNA and RNA recombination are different reflecting the specifics of DNA versus RNA replication as well as their use inside the cell. A variety of recombination mechanisms are discussed and illustrated by examples taken from specific viral species.
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