scholarly journals RNA binding is more critical to the suppression of silencing function of Cucumber mosaic virus 2b protein than nuclear localization

RNA ◽  
2012 ◽  
Vol 18 (4) ◽  
pp. 771-782 ◽  
Author(s):  
I. Gonzalez ◽  
D. Rakitina ◽  
M. Semashko ◽  
M. Taliansky ◽  
S. Praveen ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Nuclear Localization ◽  
Rna Binding ◽  
2B Protein

scholarly journals The Weak Small RNA-Binding Activity of the 2b Proteins of Subgroup II Cucumber Mosaic Virus Strains Is Insufficient for RNA Silencing Suppression

2021 ◽  
Vol 12 ◽  
Author(s):  
Yingying Gao ◽  
Jinrui Yang ◽  
Xiaobei Zhang ◽  
Aizhong Chen ◽  
Zhouhang Gu ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Rna Binding ◽  
Nuclear Accumulation ◽  
Nuclear Localization Sequence ◽  
Binding Ability ◽  
Suppressor Activity ◽  
Subgroup Ii ◽  
2B Protein

The 2b proteins encoded by cucumber mosaic virus (CMV) subgroup I strains suppress RNA silencing primarily by competitively binding small RNAs (sRNAs) in the host cell cytoplasm. Interestingly, 2b proteins encoded by CMV subgroup II strains accumulate predominantly in nuclei. Here we determined that whereas the 2b protein (Fny2b) of subgroup IA strain Fny-CMV is highly effective in suppressing both sense RNA-induced and inverted repeat-induced posttranscriptional gene silencing, the 2b protein (LS2b) of the subgroup II strain LS-CMV was not as effective. Reducing nuclear accumulation of LS2b by mutating a residue in its nuclear localization sequence had no effect on RNA silencing suppressor activity, while attenuated viral symptoms. Electrophoretic mobility shift assays showed that the sRNA binding of LS2b was weaker and more selective than that of Fny2b. The domain determining the differential sRNA-binding ability was delimited to the putative helix α1 region. Moreover, LS2b mutants that completely lost suppressor activity still retained their weak sRNA-binding ability, suggesting that sRNA binding is not sufficient for LS2b to suppress RNA silencing. Considering the subgroup I strain-encoded 2b proteins that require sRNA-binding ability for the suppression of RNA silencing, we suggest that in addition to binding sRNA, the 2b proteins of subgroup II CMV strains would require extra biological activities to achieve RNA silencing inhibition.

scholarly journals Functional analysis of the Cucumber mosaic virus 2b protein: pathogenicity and nuclear localization

2004 ◽  
Vol 85 (10) ◽  
pp. 3135-3147 ◽  
Author(s):  
Yongzeng Wang ◽  
Tzvi Tzfira ◽  
Victor Gaba ◽  
Vitaly Citovsky ◽  
Peter Palukaitis ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Nuclear Localization ◽  
Zucchini Yellow Mosaic Virus ◽  
Yellow Mosaic Virus ◽  
Silencing Suppressor ◽  
Nuclear Localization Signals ◽  
Systemic Movement ◽  
2B Protein ◽  
Function Expression

The 2b protein encoded by Cucumber mosaic virus (CMV) has been shown to be a silencing suppressor and pathogenicity determinant in solanaceous hosts, but a movement determinant in cucumber. In addition, synergistic interactions between CMV and Zucchini yellow mosaic virus (ZYMV) have been described in several cucurbit species. Here, it was shown that deletion of the 2b gene from CMV prevented extensive systemic movement of the virus in zucchini squash, which could not be complemented by co-infection with ZYMV. Thus, ZYMV expressing a silencing suppressor with a different target could not complement the CMV 2b-specific movement function. Expression of the 2b protein from an attenuated ZYMV vector resulted in a synergistic response, largely restoring infection symptoms of wild-type ZYMV in several cucurbit species. Deletion or alteration of either of two nuclear localization signals (NLSs) did not affect nuclear localization in two assays, but did affect pathogenicity in several cucurbit species, whilst deletion of both NLSs led to loss of nuclear localization. The 2b protein interacted with an Arabidopsis thaliana karyopherin α protein (AtKAPα) in the yeast two-hybrid system, as did each of the two single NLS-deletion mutants. However, 2b protein containing a deletion of both NLSs was unable to interact with AtKAPα. These data suggest that the 2b protein localizes to the nucleus by using the karyopherin α-mediated system, but demonstrate that nuclear localization was insufficient for enhancement of the 2b-mediated pathogenic response in cucurbit hosts. Thus, the sequences corresponding to the two NLSs must have another role leading to pathogenicity enhancement.

scholarly journals Symptom induction and RNA silencing suppression by the cucumber mosaic virus 2b protein

2010 ◽  
Vol 5 (6) ◽  
pp. 705-708 ◽  
Author(s):  
Mathew G. Lewsey ◽  
Inmaculada González ◽  
Natalia O. Kalinina ◽  
Peter Palukaitis ◽  
Tomas Canto ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Suppression

scholarly journals The C-terminal 33 amino acids of the cucumber mosaic virus 3a protein affect virus movement, RNA binding and inhibition of infection and translation

2004 ◽  
Vol 85 (1) ◽  
pp. 221-230 ◽  
Author(s):  
Sang Hyon Kim ◽  
Natalia O. Kalinina ◽  
Igor Andreev ◽  
Eugene V. Ryabov ◽  
Alexander G. Fitzgerald ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Binding ◽  
Virus Movement

Subcellular distribution analysis of the cucumber mosaic virus 2b protein

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 219-226 ◽  
Author(s):  
Carl N. Mayers ◽  
Peter Palukaitis ◽  
John P. Carr
Keyword(s):  
Host Cell ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Leaf Tissue ◽  
Subcellular Fractionation ◽  
Distribution Analysis ◽  
Virus Induced Gene Silencing ◽  
Pellet Fraction ◽  
2B Protein ◽  
Infected Tobacco

The cucumoviral 2b protein is a viral counterdefence factor that interferes with the establishment of virus-induced gene silencing in plants. Synthetic peptides were used to generate an antibody to the 2b protein encoded by the Fny strain of cucumber mosaic virus (Fny-CMV). This polyclonal antibody was able to recognize the Fny-CMV 2b protein in a 10000 g pellet fraction of infected tobacco. No protein of equivalent size was detected in mock-inoculated or tobacco mosaic virus-infected samples. This represents the first demonstration of 2b protein expression by a subgroup I strain of CMV. Subcellular fractionation experiments on CMV-infected tobacco leaf tissue showed that the Fny-CMV 2b protein accumulated within a fraction that sedimented at forces of less than 5000 g and that the 2b protein was solubilized only by treatment with urea or SDS. These results suggested that the 2b protein associates either with the nucleus or cytoskeleton of the host cell. Further analysis showed that the 2b protein was enriched in a fraction that sedimented through a 2·2 M sucrose cushion. This fraction was also enriched in histones, suggesting that the CMV 2b protein associates preferentially with the host cell nucleus.

Effects of the 2b Protein of Cucumber mosaic virus Subgroup IB Strain IA on Different Transgene-Induced RNA Silencing Pathways

2017 ◽  
Vol 35 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Mayuko Koizumi ◽  
Yumi Shimotori ◽  
Yuta Saeki ◽  
Sayaka Hirai ◽  
Shin-ichiro Oka ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Pathways

scholarly journals Mapping of the RNA-binding domain of the cucumber mosaic virus movement protein.

1997 ◽  
Vol 78 (8) ◽  
pp. 2095-2099 ◽  
Author(s):  
C Vaquero ◽  
J N√§hring ◽  
Y C Liao ◽  
R Fischer
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Binding ◽  
Movement Protein ◽  
Binding Domain ◽  
Virus Movement ◽  
Rna Binding Domain

scholarly journals 2b ORFs encoded by subgroup IB strains of cucumber mosaic virus induce differential virulence on Nicotiana species

2007 ◽  
Vol 88 (9) ◽  
pp. 2596-2604 ◽  
Author(s):  
Zhi-You Du ◽  
Fei-Fei Chen ◽  
Qian-Sheng Liao ◽  
Hua-Rong Zhang ◽  
Yan-Fei Chen ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Host Species ◽  
Long Distance ◽  
Reading Frame ◽  
Subgroup Ii ◽  
Viral Movement ◽  
2B Protein ◽  
Rna Accumulation ◽  
High Level

Cucumber mosaic virus (CMV)-encoded 2b protein from subgroup IA or subgroup II was shown to be a determinant of virulence in many solanaceous hosts. In this study, the virulence of 2b proteins from subgroup IB strains was analysed using four intraspecies hybrid viruses, which were generated by precise replacement of the 2b open reading frame (ORF) in subgroup IA strain Fny-CMV with the 2b ORFs of four subgroup IB strains, Cb7-CMV, PGs-CMV, Rad35-CMV and Na-CMV, generating FCb72b-CMV, FPGs2b-CMV, FRad352b-CMV and FNa2b-CMV, respectively. FCb72b-CMV was more virulent than Fny-CMV, and was similar in phenotype to its parental virus Cb7-CMV on the three Nicotiana species tested. FNa2b-CMV also was virulent on these host species, equivalent to Fny-CMV or Na-CMV. However, FRad352b-CMV only caused mild mosaic or undetectable symptoms on all the host species tested, and was less virulent than Fny-CMV or Rad35-CMV. FPGs2b-CMV infected all the host species systemically, and induced either mosaic or barely visible symptoms, demonstrating that the inability of PGs-CMV to infect these three Nicotiana species was not due to its 2b protein. The diverse virulence was shown to be mediated by the 2b proteins rather than the C-terminal overlapping parts of the 2a proteins, and was associated with the level of viral progeny RNA accumulation in systemically infected leaves, but not with the rate of long-distance viral movement in host plants. Through analysis of encapsidation of viral RNAs, there was an apparent correlation between the virulence and the high level of encapsidated RNA 2 in virions of Fny-CMV, FCb72b-CMV and FNa2b-CMV.

scholarly journals Phosphorylation regulates the subcellular localization of Cucumber Mosaic Virus 2b protein

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Katalin Nemes ◽  
Ákos Gellért ◽  
Asztéria Almási ◽  
Pál Vági ◽  
Réka Sáray ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
2B Protein
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