Structural and functional analyses of the plant host proteins associated with viral infection.

1.烟草翻译延伸因子1A（tobacco translation elongation factor 1A，eEF 1A）是烟草花叶病毒（TMV）复制复合体中的一个重要宿主因子。同时，通过与上述相同的实验表明，与TMV RNA聚合酶结合的烟草环指蛋白PHF 15是TMV感染的抑制因子.与TMV运动蛋白（MP）结合的烟草共伴侣NtDnaJ-3和与NtDnaJ-3结合的烟草转录因子NtKN 1都被证明是MP稳定积累所必需的，MP稳定积累导致受感染的细胞促进病毒3。为了阐明MP和宿主蛋白之间的相互作用所需的病毒运动，酵母双杂交筛选使用cDNA文库克隆从植物mRNA进行。马铃薯X病毒（郁金香病毒X，TVX）的TGBpl、TGBpl-2、TGBpl-3和CP的部分或全长序列，或毛细病毒（苹果茎沟病毒，A. ...更多信息 SGV）被用作诱饵。含锚定重复结构域的蛋白（ARD）被鉴定为TGBp 2相互作用蛋白。在植物中ARD敲低实验表明ARD促进TVX细胞间运动。相比之下，ASGV MP不与ARD相互作用。这些数据表明，植物病毒需要不同的宿主因子细胞间的运动取决于类型的MP。以土传小麦花叶病毒（Soil borne wheat mosaic virus，SMV）的5 ′-和3 ′-非翻译区Rep RNA 1和p152/p211复制酶基因为接种物，大麦叶肉原生质体为宿主细胞，研究了RNA复制复合物的形成。Rep RNA 1的复制在接种后9小时（hpi）达到最大值，而p152/p211翻译持续到24 hpi。p152/p211在12 hpi时在P1和S15的可溶性组分中检测到，而在24 hpi时主要在不溶性P1组分中检测到。这些结果表明，Rep RNA 1复制在感染的早期阶段，在膜结合的可溶性RNA复制复合物和p152/p211复合物积累在感染的后期阶段是不溶性的，在RNA复制中无活性。p152与p211的分子比约为4：1。少

1. A tobacco translation elongation factor 1A (eEF1A) that binds to TMV RNA polymerase was demonstrated to be an essential host factor of TMV replication complex by overexpression or suppression of eEF1A gene in the infected plants. While, a tobacco ringfinger protein PHF15 that also binds to TMV RNA polymerase was indicated to be an inhibitory factor for TMV infection by the same experiments as the above.2. A tobacco co-chaperon NtDnaJ-3 that binds to TMV movement protein (MP) and a tobacco transcription factor NtKN1 that binds to NtDnaJ-3 were both indicated to be essential for stable MP accumulation which leads the infected cell to facilitate the viral3. To elucidate the interaction between MPs and host proteins required for viral movement, yeast two-hybrid screening using cDNA library clones from plant mRNA was performed. The partial or full-length sequences of TGBpl,-2,-3, and CP of a potexvirus (Tulip virus X, TVX), or the MP and CP of a capillovirus (Apple stem grooving virus, A … More SGV) were used as bait. The ankyrin-repeat domain containing protein (ARD) was identified as a TGBp2-interacting protein. In planta ARD knock-down experiments indicated that ARD promotes TVX cell-to-cell movement. By contrast, ASGV MP did not interact with ARD. These data suggest that plant viruses require different host factors for cell-to-cell movement depending on the type of MP.4. Formation of RNA replication complexes of Soil-borne wheat mosaic virus was examined using Rep RNA1 consisting 5'-and 3'-untranslated regions and p152/p211 replicase genes as an inoculum and barley mesophyll protoplasts as host cells. Replication of Rep RNA 1 reached the maximum at 9 hours post-inoculation (hpi) while p152/p211 translation continued until 24 hpi. p152/p211 at 12 hpi were detected in soluble fractions of P1 and S15 whereas those at 24 hpi were mostly detected in an insoluble P1 fraction. These results suggest that Rep RNA 1 replicates at the early stages of infection in membrane-bound soluble RNA replication complexes and that p152/p211 complexes accumulated at the late stages of infection are insoluble and inactive in RNA replication. The molecular ratio of p152 to p211 was approximately 4 : 1. Less