Analysis of the mechanisms of tomato mosaic virus RNA replication complex formation

番茄花叶病毒（Tomato mosaic virus，ToMV）RNA的高效增殖需要宿主的七次跨膜蛋白TOM1和小的GTP结合蛋白ARL8。当使用抽空的植物原生质体提取物进行ToMV RNA体外复制反应时，使用缺乏这些蛋白质之一的拟南芥膜，负链RNA合成几乎检测不到。ToMV复制蛋白与TOM 1和ARL8共表达后，获得鸟苷酰转移酶活性，但不能催化ToMV RNA的复制。因此，与含有TOM 1和ARL8的膜的相互作用赋予ToMV复制蛋白鸟苷酰转移酶活性，然而，它不足以激活其RNA聚合酶活性。

A host seven-pass transmembrane protein TOM1 and a small GTP-binding protein ARL8 are required for efficient multiplication of tomato mosaic virus(ToMV) RNA. When in vitro ToMV RNA replication reactions using evacuolated plant protoplast extracts were performed using Arabidopsis thaliana membranes that lack either one of these proteins, negative-strand RNA synthesis was hardly detectable. When the replication protein of ToMV was co-expressed with TOM1 and ARL8, the proteins gained guanylyltransferase activity, but could not catalize ToMV RNA replication. Thus, interaction with TOM1-and ARL8-containing membranes confers guanylyltransferase activity to ToMV replication protein, however, it is not sufficient for the activation of its RNA polymerase activity.