Cascone P J, Carpenter C D, Li X H, Simon A E
Program in Molecular and Cellular Biology, University of Massachusetts, Amherst 01003.
EMBO J. 1990 Jun;9(6):1709-15. doi: 10.1002/j.1460-2075.1990.tb08294.x.
Turnip crinkle virus (TCV) is associated with satellite (sat) RNAs (sat-RNA D, sat-RNA F), defective interfering (DI) RNAs (DI RNA G, DI1 RNA), and one RNA with properties of both sat-RNAs and DI RNAs (sat-RNA C). When plants were inoculated with TCV, sat-RNA D and in vitro sat-RNA C transcripts containing non-viable mutations in the 5' domain, recombinant sat-RNAs were recovered. These recombinants were composed of sat-RNA D at the 5' end and sat-RNA C sequences at the 3' end. Analysis of 20 independent recombination junctions revealed that unequal crossing-over had occurred in planta in a region of sequence similarity between the two sat-RNAs which resulted in the duplication of 3-16 nucleotides. Thirty percent of the sat-RNA recombinants also had one to three additional nucleotides inserted at the crossover junctions which did not correspond to either sat-RNA C or sat-RNA D sequence. The right side of the recombination junctions always began with one of three consecutive nucleotides of sat-RNA C. Based on the similarity between this sequence of sat-RNA C, the right side junction of DI RNA G and the 5' end of TCV, as well as the sequence similarity between right side junctions of DI1 RNA and sat-RNA C and the 5' end of the sat-RNAs, a replicase-driven copy choice mechanism is proposed.(ABSTRACT TRUNCATED AT 250 WORDS)
芜菁皱缩病毒（TCV）与卫星（sat）RNA（sat-RNA D、sat-RNA F）、缺陷干扰（DI）RNA（DI RNA G、DI1 RNA）以及一种兼具sat-RNA和DI RNA特性的RNA（sat-RNA C）相关。当用TCV接种植物时，回收了sat-RNA D以及在5'结构域含有无活力突变的体外sat-RNA C转录本重组sat-RNA。这些重组体由5'端的sat-RNA D和3'端的sat-RNA C序列组成。对20个独立重组连接点的分析表明，在植物体内，两种sat-RNA之间序列相似的区域发生了不等交换，导致3至16个核苷酸的重复。30%的sat-RNA重组体在交换连接点还额外插入了一至三个不对应于sat-RNA C或sat-RNA D序列的核苷酸。重组连接点的右侧总是以sat-RNA C的三个连续核苷酸之一开始。基于sat-RNA C的该序列、DI RNA G的右侧连接点与TCV的5'端之间的相似性，以及DI1 RNA和sat-RNA C的右侧连接点与sat-RNA的5'端之间的序列相似性，提出了一种复制酶驱动的拷贝选择机制。（摘要截短于250字）
