Tobacco mosaic virus (TMV) replicase and movement protein function synergistically in facilitating TMV spread by lateral diffusion in the plasmodesmal desmotubule of Nicotiana benthamiana
Tobacco mosaic virus (TMV) replicase and movement protein function synergistically in facilitating TMV spread by lateral diffusion in the plasmodesmal desmotubule of Nicotiana benthamiana
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DOI：
10.1094/mpmi-21-3-0335
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发表时间：
2008-03-01
影响因子：
3.5
通讯作者：
Epel, Bernard L.
中科院分区：
文献类型：
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作者：
Guenoune-Gelbart, Dana;Elbaum, Michael;Epel, Bernard L.
病毒通过胞间连丝（Pd）传播是由病毒编码的运动蛋白（MPs）介导的，MPs修饰Pd的结构和功能。烟草花叶病毒MP （(MP)-M-TMV）是一种内质网（ER）积分膜蛋白，可与病毒RNA （vRNA）结合，形成vRNA:MP:ER复合物。据推测，TMVMP导致Pd扩张，从而增强了vRNA:MP:ER复合物通过Pd的细胞骨架滑动；相比之下，在没有MP的情况下，ER不能通过Pd。另一种模型提出，细胞间扩散是通过MP:vRNA复合物在穿过Pd的内质网膜中的扩散进行的。为了验证这些模型，我们测量了(MP)-M-TMV和复制酶表达对几种绿色荧光蛋白融合探针（可溶性细胞质蛋白、两种内质网管蛋白和两种内质网膜结合蛋白）细胞间扩散的影响。我们的数据支持扩散模型，即在感染细胞和邻近非感染细胞之间的浓度梯度的驱动下，包括ER嵌入MP、vRNA和其他成分的复合物在Pd内的ER膜中扩散。这些数据还表明，病毒复制酶和MP共同作用，改变Pd的电导率。
Virus spread through plasmodesmata (Pd) is mediated by virus-encoded movement proteins (MPs) that modify Pd structure and function. The MP of Tobacco mosaic virus ((MP)-M-TMV) is an endoplasmic reticulum (ER) integral membrane protein that binds viral RNA (vRNA), forming a vRNA:MP:ER complex. It has been hypothesized that TMVMP causes Pd to dilate, thus potentiating a cytoskeletal mediated sliding of the vRNA:MP:ER complex through Pd; in the absence of MP, by contrast, the ER cannot move through Pd. An alternate model proposes that cell-to-cell spread takes place by diffusion of the MP:vRNA complex in the ER membranes which traverse Pd. To test these models, we measured the effect of (MP)-M-TMV and replicase expression on cell-to-cell spread of several green fluorescent protein-fused probes: a soluble cytoplasmic protein, two ER lumen proteins, and two ER membrane-bound proteins. Our data support the diffusion model in which a complex that includes ER-embedded MP, vRNA, and other components diffuses in the ER membrane within the Pd driven by the concentration gradient between an infected cell and adjacent noninfected cells. The data also suggest that the virus replicase and MP function together in altering Pd conductivity.