A Multifunctional Protein Encoded by Turkey Herpesvirus Suppresses RNA Silencing in Nicotiana benthamiana
A Multifunctional Protein Encoded by Turkey Herpesvirus Suppresses RNA Silencing in Nicotiana benthamiana
复制标题
火鸡疱疹病毒编码的多功能蛋白抑制本塞姆氏烟草中的 RNA 沉默
DOI：
10.1128/jvi.05565-11
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发表时间：
2011-12-01
影响因子：
5.4
通讯作者：
Wang, Xiao-yun
中科院分区：
文献类型：
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作者：
Jing, Xiu-li;Fan, Mei-na;Wang, Xiao-yun
许多植物和动物病毒通过编码不同的RNA沉默抑制子来对抗RNA沉默介导的防御。我们鉴定了火鸡疱疹病毒（HVT）编码的多功能蛋白HVT063作为沉默抑制因子，与绿色荧光蛋白转基因benthamiana株系16c共浸润试验。我们的研究结果表明，HVT063可以强烈抑制由感觉RNA或双链RNA （dsRNA）诱导的局部和全身RNA沉默。HVT063可以逆转新生叶片的局部沉默，但不能逆转系统性沉默。利用异源载体PVX验证了HVT063的局部沉默抑制活性。此外，HVT063蛋白精氨酸或赖氨酸残基的单丙氨酸替代表明，每个选择的单氨基酸都对HVT063的抑制活性有贡献，而1区（残基138至141）更为重要，因为该区域的4个单氨基酸突变中有3个可以消除HVT063的沉默抑制活性。此外，HVT063似乎在浸润叶区诱导细胞死亡表型，稀释HVT063可以降低沉默抑制子活性，减轻细胞死亡表型。总之，这些结果表明HVT063作为RNA沉默的病毒抑制因子，在RNA沉默过程中靶向dsRNA形成的下游步骤。HVT063中带正电的氨基酸，如精氨酸和赖氨酸，可能通过促进HVT063与RNA之间的相互作用来促进抑制活性，因为HVT063已被证明是一种RNA结合蛋白。
ABSTRACT Many plant and animal viruses counteract RNA silencing-mediated defense by encoding diverse RNA silencing suppressors. We characterized HVT063, a multifunctional protein encoded by turkey herpesvirus (HVT), as a silencing suppressor in coinfiltration assays with green fluorescent protein transgenic Nicotiana benthamiana line 16c. Our results indicated that HVT063 could strongly suppress both local and systemic RNA silencing induced by either sense RNA or double-stranded RNA (dsRNA). HVT063 could reverse local silencing, but not systemic silencing, in newly emerging leaves. The local silencing suppression activity of HVT063 was also verified using the heterologous vector PVX. Further, single alanine substitution of arginine or lysine residues of the HVT063 protein showed that each selected single amino acid contributed to the suppression activity of HVT063 and region 1 (residues 138 to 141) was more important, because three of four single amino acid mutations in this region could abolish the silencing suppressor activity of HVT063. Moreover, HVT063 seemed to induce a cell death phenotype in the infiltrated leaf region, and the HVT063 dilutions could decrease the silencing suppressor activity and alleviate the cell death phenotype. Collectively, these results suggest that HVT063 functions as a viral suppressor of RNA silencing that targets a downstream step of the dsRNA formation in the RNA silencing process. Positively charged amino acids in HVT063, such as arginine and lysine, might contribute to the suppressor activity by boosting the interaction between HVT063 and RNA, since HVT063 has been demonstrated to be an RNA binding protein.