A Host Protein Interacting With a Tombusvirus Cell-to-Cell Movement Protein

病毒是研究植物中大分子运输的合适工具，因为它们编码特殊的运动蛋白(MPS)，使这些病原体能够通过胞间连丝在细胞之间移动。此外，番茄丛矮病毒(TBSV)单链正链RNA基因组编码的MP在许多不同的家族中都具有功能。最近的数据表明，TBSV MP与一种新的宿主因子(HF3.5)相互作用，该宿主因子与一类已知通过胞间连丝运输的转录因子具有相似性。体内和体外与定义的MP突变体的结合试验结果支持了HF3.5与TBSV MP之间的相互作用在功能上相关的假设。本项目的目的是通过以下几个方面进一步验证这一假说：i)P22-HF3.5相互作用的详细分子分析，ii)HF3.5蛋白在植物中的定位，iii)植物提取物中P22与宿主蛋白相互作用的生化验证，以及IV)通过监测HF3.5基因沉默对TBSV运动和感染的影响来研究其功能作用。预计对这种新描述的运动相关宿主蛋白的研究将为控制病毒和其他大分子在植物中运动的相互作用提供新的见解。

Viruses are suitable tools to study trafficking of macromolecules through plants because they encode specialized movement proteins (MPs) that enable these pathogens to move cell to cell via the plasmodesmata. Moreover, the MP encoded by the single-stranded positive-sense RNA genome of Tomato bushy stunt virus (TBSV) is functional in many different families. Recent data have shown that the TBSV MP interacts with a novel host factor (HF3.5) with similarities to a class of transcription factors that are known to traffic through plasmodesmata. Results of in vivo and in vitro binding tests with defined MP mutants provided support for the hypothesis that the interaction between HF3.5 and the TBSV MP is functionally relevant. The objectives of this project aim to further test this hypothesis by: I) a detailed molecular analysis of the P22-HF3.5 interaction, II) localization of the HF3.5 protein in planta, III) biochemical verification of P22-host protein interactions in plant extracts, and IV) studying the functional role by monitoring the effect of HF3.5 gene silencing on TBSV movement and infection. It is anticipated that the studies of this newly described movement-associated host protein will provide novel insights into the interactions that control movement of viruses and other macromolecules through plants.