The Weak Small RNA-Binding Activity of the 2b Proteins of Subgroup II Cucumber Mosaic Virus Strains Is Insufficient for RNA Silencing Suppression.
The Weak Small RNA-Binding Activity of the 2b Proteins of Subgroup II Cucumber Mosaic Virus Strains Is Insufficient for RNA Silencing Suppression.
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II型黄瓜花叶病毒株2b蛋白的弱小RNA结合活性不足以抑制RNA沉默
DOI：
10.3389/fmicb.2021.760937
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发表时间：
2021
影响因子：
5.2
通讯作者：
Du Z
中科院分区：
文献类型：
--
作者：
Gao Y;Yang J;Zhang X;Chen A;Gu Z;Du Z
黄瓜花叶病毒 (CMV) I 亚型菌株编码的 2b 蛋白主要通过竞争性结合宿主细胞细胞质中的小 RNA (sRNA) 来抑制 RNA 沉默。有趣的是，CMV II 亚型毒株编码的 2b 蛋白主要在细胞核中积累。在这里，我们确定，虽然亚型 IA 菌株 Fny-CMV 的 2b 蛋白 (Fny2b) 在抑制有义 RNA 诱导的和反向重复诱导的转录后基因沉默方面非常有效，但亚型 II 菌株 LS-CMV 的 2b 蛋白 (LS2b) 则不那么有效。通过突变核定位序列中的残基来减少 LS2b 的核积累，对 RNA 沉默抑制子活性没有影响，同时减弱了病毒症状。电泳迁移率变动分析表明，LS2b 的 sRNA 结合比 Fny2b 更弱且选择性更高。决定差异 sRNA 结合能力的结构域被界定为假定的螺旋 α1 区域。此外，完全失去抑制活性的LS2b突变体仍然保留了其较弱的sRNA结合能力，这表明sRNA结合不足以让LS2b抑制RNA沉默。考虑到亚组I毒株编码的2b蛋白需要sRNA结合能力来抑制RNA沉默，我们建议除了结合sRNA之外，亚组II CMV毒株的2b蛋白还需要额外的生物活性来实现RNA沉默抑制。
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.
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影响因子：
3.5
作者：
Gonzalez, Inmaculada;Martinez, Llucia;Canto, Tomas
通讯作者：
Canto, Tomas
影响因子：
11.6
作者：
Diaz-Pendon, Juan A.;Li, Feng;Ding, Shou-Wei
通讯作者：
Ding, Shou-Wei
黄瓜花叶病毒 2b N 末端附近的两个氨基酸在抑制 RNA 沉默和病毒感染性中发挥着关键作用。
影响因子：
4.9
作者：
Dong, Kai;Wang, Ying;Wang, Xian-Bing
通讯作者：
Wang, Xian-Bing
影响因子：
4.6
作者：
Nemes K;Gellért Á;Almási A;Vági P;Sáray R;Kádár K;Salánki K
通讯作者：
Salánki K
影响因子：
6.7
作者：
Li F;Huang C;Li Z;Zhou X
通讯作者：
Zhou X