Analysis of Processes Associated with Replication of Subviral RNAs in the TCV System

植物病毒和亚病毒rna复制和产生疾病症状的过程尚不清楚。一个特别有趣的问题涉及线性亚病毒RNA多聚体的起源。一个提出的模型表明，在同一系统中，多聚体的形成过程与不连续rna的产生过程相同；复制酶在释放新合成的链之前重新开始合成。该模型将通过跟踪原生质体复制系统中多聚体和单体的形成以及分析影响体内产生的单体和多聚体比例的不同卫星RNA突变来进行测试。第二个问题涉及到最近的一项发现，即在植物中积累的亚病毒RNA的特定情况下，重复复制冗余核苷酸可能发生。在某些动物病毒中，这个被称为复制酶口吃的过程导致了隐读框的暴露。将使用缺失分析和体外诱变技术对涉及核苷酸添加区域稳定的茎环结构的模型进行测试。重复核苷酸复制的生理作用的可能性将通过将“口吃盒”转移到异源病毒RNA并测试其插入额外非编码核苷酸的能力来解决。//

The processes by which plant viral and subviral RNAs replicate and produce disease symptoms are not understood. One particularly intriguing question concerns the origin of linear subviral RNA multimers. A proposed model suggests that multimers are formed by the same process as the generation of discontinuous RNAs in the same system; the replicase reinitiates synthesis before releasing the newly synthesized strand. This model will be tested by following the formation of multimers and monomers in a protoplast replication system as well as analyzing different satellite RNA mutations which affect the ratio of monomers and multimers produced in vivo. A second question involves the recent finding that reiterative copying of redundant nucleotide can occur under specific circumstances in a subviral RNA accumulating in plants. In certain animal viruses, this process, known as replicase stuttering, results in the exposure of cryptic reading frames. A model involving a stable stem loop structure in the region of the nucleotide additions will be tested using deletion analysis and in vitro mutagenesis techniques. The possibility of a physiological role for reiterative nucleotide copying will be addressed by transferring a "stuttering cassette" to a heterologous viral RNA and testing for the ability to insert additional, non- encoded nucleotides. //