scholarly journals Use of a vector based on Potato virus X in a whole plant assay to demonstrate nuclear targeting of Potato spindle tuber viroid

2001 ◽  
Vol 82 (6) ◽  
pp. 1491-1497 ◽  
Author(s):  
Yan Zhao ◽  
Robert A. Owens ◽  
Rosemarie W. Hammond

Potato spindle tuber viroid (PSTVd) is a covalently closed circular RNA molecule of 359 nucleotides that replicates within the nucleus of host cells. To determine how this small, highly structured RNA enters the nucleus, we have developed a virus-based, whole plant in vivo assay that uses green fluorescent protein (GFP) as the reporter molecule. The coding region of GFP was interrupted by insertion of an intron derived from the intervening sequence 2 of the potato ST-LS1 gene. A cDNA copy of the complete PSTVd genome was, in turn, embedded within the intron, and this construct was delivered into Nicotiana benthamiana plants via a vector based on Potato virus X. The intron-containing GFP subgenomic RNA synthesized during virus infection cannot produce a functional GFP unless the RNA is imported into the nucleus, where the intron can be removed and the spliced RNA returned to the cytoplasm. The appearance of green fluorescence in leaf tissues inoculated with constructs containing a full-length PSTVd molecule embedded in the intron indicates that nuclear import and RNA splicing events did occur.

2009 ◽  
Vol 83 (15) ◽  
pp. 7761-7769 ◽  
Author(s):  
Heidrun-Katharina Draghici ◽  
Mark Varrelmann

ABSTRACT Recombination in RNA viruses, one of the main factors contributing to their genetic variability and evolution, is a widespread phenomenon. In this study, an in vivo assay to characterize RNA recombination in potato virus X (PVX), under high selection pressure, was established. Agrobacterium tumefaciens was used to express in Nicotiana benthamiana leaf tissue both a PVX isolate labeled with green fluorescent protein (GFP) containing a coat protein deletion mutation (ΔCP) and a transcript encoding a functional coat protein +3′-ntr. Coexpression of the constructs led to virus movement and systemic infection; reconstituted recombinants were observed in 92% of inoculated plants. Similar results were obtained using particle bombardment, demonstrating that recombination mediated by A. tumefaciens was not responsible for the occurrence of PXC recombinants. The speed of recombination could be estimated by agroinfection of two PVX mutants lacking the 3′ and 5′ halves of the genome, respectively, with an overlap in the triple gene block 1 gene, allowing GFP expression only in the case of recombination. Ten different pentapeptide insertion scanning replicase mutants with replication abilities comparable to wild-type virus were applied in the different recombination assays. Two neighboring mutants affecting the linker between the methyltransferase and helicase domains were shown to be strongly debilitated in their ability to recombine. The possible functional separation of replication and recombination in the replicase molecule supports the model that RNA recombination represents a distinct function of this protein, although the underlying mechanism still needs to be investigated.


2021 ◽  
Vol 118 (42) ◽  
pp. e2110887118
Author(s):  
Qiang Wang ◽  
Lin Zhang ◽  
Guo-Wei Zhang ◽  
Jian-Hua Mao ◽  
Xiao-Dong Xi ◽  
...  

Infusing CRISPR/donor-loaded adeno-associated viral vectors (AAV/CRISPR) could enable in vivo hepatic gene editing to remedy hemophilia B (HB) with inherited deficiency of clotting factor IX (FIX). Yet, current regimens focus on correcting HB with simple mutations in the coding region of the F9, overlooking those carrying complicated mutations involving the regulatory region. Moreover, a possible adverse effect of treatment-related inflammation remains unaddressed. Here we report that a single DNA cutting-mediated long-range replacement restored the FIX-encoding function of a mutant F9 (mF9) carrying both regulatory and coding defects in a severe mouse HB model, wherein incorporation of a synthetic Alb enhancer/promoter-mimic (P2) ensured FIX elevation to clinically meaningful levels. Through single-cell RNA sequencing (scRNA-seq) of liver tissues, we revealed that a subclinical hepatic inflammation post-AAV/CRISPR administration regulated the vulnerability of the edited mF9-harboring host cells to cytotoxic T lymphocytes (CTLs) and the P2 activity in a hepatocytic subset–dependent manner via modulating specific sets of liver-enriched transcription factors (LETFs). Collectively, our study establishes an AAV/CRISPR-mediated gene-editing protocol applicable to complicated monogenetic disorders, underscoring the potentiality of improving therapeutic benefits through managing inflammation.


2021 ◽  
Vol 1 (19) ◽  
pp. 242-244
Author(s):  
A.V. Ivanov ◽  
A.V. Zherdev ◽  
B.B. Dzantiev

Test systems have been developed for the detection of phytopathogens, combining recombinase polymerase amplification and membrane test strips. Test systems provide detection of potato virus X, potato spindle tuber viroid, potato blackleg pathogen (Dickeya solani), as well as multi-analysis of three viruses. Amplification is carried out at 37 °C. The analysis time does n ot exceed 30 min.


2015 ◽  
Vol 10 (2) ◽  
pp. 86-94 ◽  
Author(s):  
Soad H. Taha ◽  
Samah A. Mokbel ◽  
Mahmoud Abdel- Hamid ◽  
Ali H. Hamed

2008 ◽  
Vol 21 (2) ◽  
pp. 178-187 ◽  
Author(s):  
Shahid Aslam Siddiqui ◽  
Cecilia Sarmiento ◽  
Erkki Truve ◽  
Harry Lehto ◽  
Kirsi Lehto

RNA silencing suppressor genes derived from six virus genera were transformed into Nicotiana benthamiana and N. tabacum plants. These suppressors were P1 of Rice yellow mottle virus (RYMV), P1 of Cocksfoot mottle virus, P19 of Tomato bushy stunt virus, P25 of Potato virus X, HcPro of Potato virus Y (strain N), 2b of Cucumber mosaic virus (strain Kin), and AC2 of African cassava mosaic virus (ACMV). HcPro caused the most severe phenotypes in both Nicotiana spp. AC2 also produced severe effects in N. tabacum but a much milder phenotype in N. benthamiana, although both HcPro and AC2 affected the leaf tissues of the two Nicotiana spp. in similar ways, causing hyperplasia and hypoplasia, respectively. P1-RYMV caused high lethality in the N. benthamiana plants but only mild effects in the N. tabacum plants. Phenotypic alterations produced by the other transgenes were minor in both species. Interestingly, the suppressors had very different effects on crucifer-infecting Tobamovirus (crTMV) infections. AC2 enhanced both spread and brightness of the crTMV-green fluorescent protein (GFP) lesions, whereas 2b and both P1 suppressors enhanced spread but not brightness of these lesions. P19 promoted spread of the infection into new foci within the infiltrated leaf, whereas HcPro and P25 suppressed the spread of crTMV-GFP lesions.


2015 ◽  
Vol 28 (7) ◽  
pp. 739-750 ◽  
Author(s):  
Matevz Rupar ◽  
Florence Faurez ◽  
Michel Tribodet ◽  
Ion Gutiérrez-Aguirre ◽  
Agnès Delaunay ◽  
...  

Potato virus Y (PVY) is an economically important plant virus that infects Solanaceous crops such as tobacco and potato. To date, studies into the localization and movement of PVY in plants have been limited to detection of viral RNA or proteins ex vivo. Here, a PVY N605 isolate was tagged with green fluorescent protein (GFP), characterized and used for in vivo tracking. In Nicotiana tabacum cv. Xanthi, PVY N605-GFP was biologically comparable to nontagged PVY N605, stable through three plant-to-plant passages and persisted for four months in infected plants. GFP was detected before symptoms and fluorescence intensity correlated with PVY RNA concentrations. PVY N605-GFP provided in vivo tracking of long-distance movement, allowing estimation of the cell-to-cell movement rate of PVY in N. tabacum cv. Xanthi (7.1 ± 1.5 cells per hour). PVY N605-GFP was adequately stable in Solanum tuberosum cvs. Désirée and NahG-Désirée and able to infect S. tuberosum cvs. Bintje and Bea, Nicotiana benthamiana, and wild potato relatives. PVY N605-GFP is therefore a powerful tool for future studies of PVY-host interactions, such as functional analysis of viral and plant genes involved in viral movement.


2005 ◽  
Vol 86 (8) ◽  
pp. 2379-2391 ◽  
Author(s):  
M. V. Schepetilnikov ◽  
U. Manske ◽  
A. G. Solovyev ◽  
A. A. Zamyatnin ◽  
J. Schiemann ◽  
...  

Potato virus X (PVX) encodes three movement proteins, TGBp1, TGBp2 and TGBp3. The 8 kDa TGBp3 is a membrane-embedded protein that has an N-terminal hydrophobic sequence segment and a hydrophilic C terminus. TGBp3 mutants with deletions in the C-terminal hydrophilic region retain the ability to be targeted to cell peripheral structures and to support limited PVX cell-to-cell movement, suggesting that the basic TGBp3 functions are associated with its N-terminal transmembrane region. Fusion of green fluorescent protein to the TGBp3 N terminus abrogates protein activities in intracellular trafficking and virus movement. The intracellular transport of TGBp3 from sites of its synthesis in the rough endoplasmic reticulum (ER) to ER-derived peripheral bodies involves a non-conventional COPII-independent pathway. However, integrity of the C-terminal hydrophilic sequence is required for entrance to this non-canonical route.


2001 ◽  
Vol 14 (10) ◽  
pp. 1158-1167 ◽  
Author(s):  
Atsushi Tamai ◽  
Tetsuo Meshi

Potato virus X (PVX) requires three proteins, p25, p12, and p8, encoded by the triple gene block plus the coat protein (CP) for cell-to-cell movement. When each of these proteins was co-expressed with a cytosolic green fluorescent protein (GFP) in the epidermal cells of Nicotiana benthamiana by the microprojectile bombardment-mediated gene delivery method, only p12 enhanced diffusion of co-expressed GFP, indicating an ability to alter plasmodesmal permeability. p25, p12, and CP, expressed transiently in the initially infected cells, transcomplemented the corresponding movement-defective mutants to spread through two or more cell boundaries. Thus, these proteins probably move from cell to cell with the genomic RNA. In contrast, p8 only functioned intracellularly and was not absolutely required for cell-to-cell movement. Since overexpression of p12 overcame the p8 deficiency, p8 appears to facilitate the functioning of p12, presumably by mediating its intracellular trafficking. Considering the likelihood that p12 and p8 are membrane proteins, it is suggested that intercellular as well as intracellular movement of PVX involves a membrane-mediated process.


2011 ◽  
Vol 23 (1) ◽  
pp. 263 ◽  
Author(s):  
C. W. O'Gorman ◽  
J. Zhao ◽  
M. S. Samuel ◽  
E. M. Walters ◽  
R. S. Prather ◽  
...  

Proteasomes are large protein complexes involved in protein degradation in eukaryotes and undergo dynamic redistribution between cellular compartments. Characterising the cellular localization of proteasomes at various stages of development and in response to stimuli is of interest. We hypothesised that porcine proteasomes could be visualised in vivo via a ubiquitously expressed transgene fusion comprising a proteasomal subunit and green florescent protein (GFP). The full-length sequence for porcine PSMA-1 was first constructed in silico from public data and was used to retrieve a GenBank expressed sequence tag (EST) sequence that appeared to be full length (accession CO946059; kind gift from R. S. Prather). Primers were designed to remove the stop codon and create homology for cloning with InFusion (Clontech, Palo Alto, CA, USA). The amplimer was inserted into pCAG-CreGFP (Addgene plasmid 13776) in place of the Cre coding region. The resulting plasmid (pKW14) was screened via restriction digest and sequenced for confirmation. This plasmid was confirmed functional in porcine fetal fibroblasts. After removal of the plasmid backbones, pKW14, a G418 resistance cassette (NEO), and the chicken egg white matrix attachment region were co-electroporated into male fetal fibroblasts (10 μg of total DNA, 5:2:2 ratio, respectively). Cells were grown in DMEM with 10% fetal bovine serum (FBS) and selection was initiated 36 h after transfection. Following 12 days of selection at 400 mg L–1 G418, colonies were screened by epifluorescence. Positive colonies were harvested and confirmed transgenic for all 3 input DNAs. Positive colonies were randomly pooled as sets of 3 independent integration events. Embryos were reconstructed via SCNT and transferred to 2 recipients. The fusion rates were 70 and 78%, respectively, with transfer numbers of 120 and 125 fused couplets being transferred into synchronized recipients on Day 0 of heat. Both recipients became pregnant and delivered 2 piglets each on Day 114 by Caesarean section. One live piglet was produced from each litter. Of the 2 live-born piglets, 1 survived beyond Day 3 and continues to be healthy. Transgenic status was verified by PCR. Expression was confirmed by epifluorescence of GFP-labelled proteasomes. This founder will be used to establish a model to evaluated cellular localization of proteasomes in vivo and in culture.


2004 ◽  
Vol 377 (3) ◽  
pp. 641-651 ◽  
Author(s):  
Wenzheng ZHANG ◽  
Yoshihide HAYASHIZAKI ◽  
Bruce C. KONE

Recently, a new class of histone methyltransferases that plays an indirect role in chromatin silencing by targeting a conserved lysine residue in the nucleosome core was described, namely the Dot1 (disruptor of telomeric silencing) family [Feng, Wang, Ng, Erdjument-Bromage, Tempst, Struhl and Zhang (2002) Curr. Biol. 12, 1052–1058; van Leeuwen, Gafken and Gottschling (2002) Cell (Cambridge, Mass.) 109, 745–756; Ng, Feng, Wang, Erdjument-Bromage, Tempst, Zhang and Struhl (2002) Genes Dev. 16, 1518–1527]. In the present study, we report the isolation, genomic organization and in vivo expression of a mouse Dot1 homologue (mDot1). Expressed sequence tag analysis identified five mDot1 mRNAs (mDot1a–mDot1e) derived from alternative splicing. mDot1a and mDot1b encode 1540 and 1114 amino acids respectively, whereas mDot1c–mDot1e are incomplete at the 5´-end. mDot1a is closest to its human counterpart (hDot1L), sharing 84% amino acid identity. mDot1b is truncated at its N- and C-termini and contains an internal deletion. The five mDot1 isoforms are encoded by 28 exons on chromosome 10qC1, with exons 24 and 28 further divided into two and four sections respectively. Alternative splicing occurs in exons 3, 4, 12, 24, 27 and 28. Northern-blot analysis with probes corresponding to the methyltransferase domain or the mDot1a-coding region detected 7.6 and 9.5 kb transcripts in multiple tissues, but only the 7.6 kb transcript was evident in mIMCD3-collecting duct cells. Transfection of mDot1a–EGFP constructs (where EGFP stands for enhanced green fluorescent protein) into human embryonic kidney (HEK)-293T or mIMCD3 cells increased the methylation of H3-K79 but not H3-K4, -K9 or -K36. Furthermore, DMSO induced mDot1 gene expression and methylation specifically at H3-K79 in mIMCD3 cells in a time- and dose-dependent manner. Collectively, these results add new members to the Dot1 family and show that mDot1 is involved in a DMSO-mediated signal-transduction pathway in collecting duct cells.


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