Downregulation of the NbNACa1 gene encoding a movement-protein-interacting protein reduces cell-to-cell movement of Brome mosaic virus in Nicotiana benthamiana.
Downregulation of the NbNACa1 gene encoding a movement-protein-interacting protein reduces cell-to-cell movement of Brome mosaic virus in Nicotiana benthamiana.
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DOI：
10.1094/mpmi-20-6-0671
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发表时间：
2007-05
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影响因子：
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通讯作者：
M. Kaido;Yosuke Inoue;Yoshika Takeda;K. Sugiyama;A. Takeda;M. Mori;A. Tamai;T. Meshi;T. Okuno;K. Mise
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作者：
M. Kaido;Yosuke Inoue;Yoshika Takeda;K. Sugiyama;A. Takeda;M. Mori;A. Tamai;T. Meshi;T. Okuno;K. Mise
3a运动蛋白（MP）在RNA植物病毒溴花叶病毒（BMV）的运动中起核心作用。为了确定参与病毒运动的宿主因子基因，以重组BMV MP为探针，采用远western blotting技术筛选了BMV系统宿主烟性白烟（Nicotiana benthamiana） cDNA文库。一个阳性克隆编码的蛋白质序列与来自各种生物体的新生多肽相关复合物的α链相似，这有助于新合成蛋白质的易位保真度。该同源基因被命名为NbNACa1。在体内用农业浸润免疫沉淀法证实了NbNACa1与BMV MP的结合。为了研究NbNACa1在BMV增殖中的作用，我们培育了NbNACa1沉默（GSNAC）转基因benthamiana植株。下调NbNACa1表达可减少病毒在接种叶片中的积累，但在原生质体中没有。一项监测bmv - mp辅助病毒运动的微弹轰击试验表明，病毒在GSNAC植物中的传播减少。在GSNAC植物中，与绿色荧光蛋白融合的BMV MP在细胞壁上的定位延迟。根据这些结果，我们提出NbNACa1通过调节BMV MP向胞间连丝的定位参与了BMV细胞间的运动。
The 3a movement protein (MP) plays a central role in the movement of the RNA plant virus, Brome mosaic virus (BMV). To identify host factor genes involved in viral movement, a cDNA library of Nicotiana benthamiana, a systemic host for BMV, was screened with far-Western blotting using a recombinant BMV MP as probe. One positive clone encoded a protein with sequence similarity to the alpha chain of nascent-polypeptide-associated complex from various organisms, which is proposed to contribute to the fidelity of translocation of newly synthesized proteins. The orthologous gene from N. benthamiana was designated NbNACa1. The binding of NbNACa1 to BMV MP was confirmed in vivo with an agroinfiltration-immunoprecipitation assay. To investigate the involvement of NbNACa1 in BMV multiplication, NbNACa1-silenced (GSNAC) transgenic N. benthamiana plants were produced. Downregulation of NbNACa1 expression reduced virus accumulation in inoculated leaves but not in protoplasts. A microprojectile bombardment assay to monitor BMV-MP-assisted viral movement demonstrated reduced virus spread in GSNAC plants. The localization to the cell wall of BMV MP fused to green fluorescent protein was delayed in GSNAC plants. From these results, we propose that NbNACa1 is involved in BMV cell-to-cell movement through the regulation of BMV MP localization to the plasmodesmata.