Subviral RNAs of TCV: Symptom Induction and the Generation of Discontinous RNAs

芜菁皱缩病毒（TCV）将被用作研究症状的模型 表现，缺陷性干扰（DI）RNA形成和RNA 重组 TCV系统是唯一适合这些 研究;它是唯一的植物或动物病毒与 无毒和有毒的卫星RNA，可以重组它们的基因组 和DI RNA，其可以从体外从头产生， 合成TCV转录物。 此外，TCV的两个分离株具有 独特的生物学特性：亚病毒RNA只产生症状 当与TCV-M分离株和DI RNA相关时， 从TCV-B分离物产生。 嵌合TCV基因组RNA将 以确定TCV RNA的哪个区域参与了 差异症状产生和DI形成。 机制 通过其形成DI RNA和sat-RNA重组体也将被 研究了 假定的内部复制酶识别序列 在sat-RNA C中，在所有重组体的右手连接处发现 卫星RNA，将被删除，改变和/或从其当前的 位置，以确定序列的重要性， 重组 拷贝选择模型与断裂和连接 还将测试用于形成后代RNA的模型。 具有确定突变的Sat-RNA转录物，允许差异 复制的正链或负链，将被添加到两者 原生质体和植物提取物。 将检测到RNA重组 聚合酶链反应技术 *

Turnip crinkle virus (TCV) will be used as a model to study symptom manifestation, defective interfering (DI) RNA formation and RNA recombination. The TCV system is uniquely suited for these studies; it is the only plant or animal virus associated with avirulent and virulent sat-RNAs which can recombine their genomes and DI RNAs which can be generated de novo from in vitro synthesized TCV transcripts. Furthermore, two isolates of TCV have distinct biological properties: subviral RNAs only produce symptoms when associated with the TCV-M isolate and DI RNAs have only been generated from the TCV-B isolate. Chimeric TCV genomic RNAs will be constructed to ascertain which region of TCV RNA is involved in differential symptom production and DI formation. The mechanism by which DI RNAs and sat-RNA recombinants are formed will also be investigated. The putative internal replicase recognition sequence in sat-RNA C, found at the right hand junction of all recombinant sat-RNAs, will be deleted, altered and/or moved from its current location to determine the importance of the sequence in recombination. A copy choice model versus a breakage and ligation model for the formation of descendance RNAs will also be tested. Sat-RNA transcripts with defined mutations, allowing differential replication of plus or minus strands, will be added to both protoplasts and plant extracts. RNA recombination will be detected by polymerase chain reaction techniques.***//