Genetic link between RNAi/PTGS & viral RNA recombination

描述(申请人提供)：雀麦花叶病毒(BMV)系统是了解RNA重组在正链RNA病毒中作用的极好模型。最近，我们确定了雀麦花叶病毒(BMV)，一种模型正链RNA病毒，可以在拟南芥中复制和重组(Dzianott和Bujarski，病毒学2004)。我们的长期目标是阐明宿主基因在病毒RNA重组中的作用。具体的假设是RNA干扰(RNAi/PTGS)途径参与了病毒RNA重组体的产生。我们的这一假设是基于在拟南芥中观察到的：(I)RNAi/PTGS的抑制子抑制了一种由双链结构支持的RNA重组；(Ii)敲除了Argonaute基因抑制了拟南芥中的非同源重组；以及(Iii)同源重组受到的影响小于非同源重组。基于这些数据，这一应用的实验重点是在携带受影响的RNAi/PTGS途径的拟南芥品系中进行BMV RNA重组。具体目标是： 1.以拟南芥突变株系为材料，研究了Dice相关寄主基因在重组中的作用。 2.以拟南芥突变系为材料，研究后Dester相关寄主基因在重组中的作用。

DESCRIPTION (provided by applicant): The Brome mosaic virus (BMV) system is an excellent model for understanding the role of RNA recombination in plus-strand RNA viruses. Recently we have determined that Brome mosaic virus (BMV), a model plus-strand RNA virus, could replicate and recombine in Arabidopsis thaliana (Dzianott and Bujarski, Virology 2004). Our long term goal is to elucidate the role of the host genes in viral RNA recombination. The specific hypothesis is that the RNA interference (RNAi/PTGS) pathway participates in the generation of viral RNA recombinants. We base that hypothesis on the observations in Arabidopsis that: (i) the suppressor of RNAi/PTGS inhibited a type of RNA recombination that was supported by double-stranded structures; (ii) knocking-out an Argonaute gene inhibited non-homologous recombination in Arabidopsis; and (iii) homologous recombination was affected to a lesser extent than non-homologous recombination. Based on these data, the experimental focus of this application is on BMV RNA recombination in the Arabidopsis lines carrying the affected RNAi/PTGS pathway. The specific aims are to: 1. Characterize the role of DICER related host genes in recombination by using the Arabidopsis mutant lines. 2. Characterize the role of post-DICER related host genes in recombination by using the Arabidopsis mutant lines.