Verchot-Lubicz Jeanmarie, Ye Chang-Ming, Bamunusinghe Devinka
Oklahoma State University, Department of Entomology and Plant Pathology, 127 Noble Research Center, Stillwater, OK 74078, USA.
J Gen Virol. 2007 Jun;88(Pt 6):1643-1655. doi: 10.1099/vir.0.82667-0.
Recent advances in potexvirus research have produced new models describing virus replication, cell-to-cell movement, encapsidation, R gene-mediated resistance and gene silencing. Interactions between distant RNA elements are a central theme in potexvirus replication. The 5' non-translated region (NTR) regulates genomic and subgenomic RNA synthesis and encapsidation, as well as virus plasmodesmal transport. The 3' NTR regulates both plus- and minus-strand RNA synthesis. How the triple gene-block proteins interact for virus movement is still elusive. As the potato virus X (PVX) TGBp1 protein gates plasmodesmata, regulates virus translation and is a suppressor of RNA silencing, further research is needed to determine how these properties contribute to propelling virus through the plasmodesmata. Specifically, TGBp1 suppressor activity is required for virus movement, but how the silencing machinery relates to plasmodesmata is not known. The TGBp2 and TGBp3 proteins are endoplasmic reticulum (ER)-associated proteins required for virus movement. TGBp2 associates with ER-derived vesicles that traffic along the actin network. Future research will determine whether the virus-induced vesicles are cytopathic structures regulating events along the ER or are vehicles carrying virus to the plasmodesmata for transfer into neighbouring cells. Efforts to assemble virions in vitro identified a single-tailed particle (STP) comprising RNA, coat protein (CP) and TGBp1. It has been proposed that TGBp1 aids in transport of virions or STP between cells and ensures translation of RNA in the receiving cells. PVX is also a tool for studying Avr-R gene interactions and gene silencing in plants. The PVX CP is the elicitor for the Rx gene. Recent reports of the PVX CP reveal how CP interacts with the Rx gene product.
马铃薯X病毒研究的最新进展产生了新的模型，用于描述病毒复制、细胞间移动、衣壳化、R基因介导的抗性和基因沉默。远距离RNA元件之间的相互作用是马铃薯X病毒复制的核心主题。5'非翻译区（NTR）调节基因组和亚基因组RNA的合成、衣壳化以及病毒胞间连丝运输。3'NTR调节正链和负链RNA的合成。三联基因块蛋白如何相互作用以实现病毒移动仍不清楚。由于马铃薯X病毒（PVX）TGBp1蛋白控制胞间连丝、调节病毒翻译并且是RNA沉默的抑制因子，因此需要进一步研究来确定这些特性如何有助于病毒通过胞间连丝传播。具体而言，病毒移动需要TGBp1抑制活性，但沉默机制与胞间连丝的关系尚不清楚。TGBp2和TGBp3蛋白是病毒移动所需的内质网（ER）相关蛋白。TGBp2与沿着肌动蛋白网络运输的ER衍生囊泡相关联。未来的研究将确定病毒诱导的囊泡是调节内质网相关事件的细胞病变结构，还是将病毒携带到胞间连丝以转移到相邻细胞的载体。体外组装病毒粒子的研究确定了一种单尾粒子（STP），其包含RNA、衣壳蛋白（CP）和TGBp1。有人提出，TGBp1有助于病毒粒子或STP在细胞间运输，并确保RNA在接收细胞中翻译。PVX也是研究植物中Avr - R基因相互作用和基因沉默的工具。PVX CP是Rx基因的激发子。最近关于PVX CP的报道揭示了CP与Rx基因产物的相互作用方式。
