Buzayan J M, van Tol H, Zalloua P A, Bruening G
Department of Plant Pathology, College of Agricultural and Environmental Sciences, University of California, Davis 95616, USA.
Virology. 1995 Apr 20;208(2):832-7. doi: 10.1006/viro.1995.1221.
A small satellite RNA of tobacco ringspot virus (sTRSV RNA) generates circular and linear molecules of unit length and repetitive sequence, linear multimers during replication. The phosphodiester junction joining the unit satellite RNA sequences in multimeric and circular RNA resisted base-catalyzed cleavage in circles but not in linear dimers. We postulate that junctions of multimeric satellite RNA form during synthesis of the polyribonucleotide chain, whereas those of circular RNA result from a ligation reaction that introduces a group blocking the junction 2'-hydroxyl. To test the relative effectiveness of linear and circular satellite RNAs in initiating replication, we inoculated onto bean (Phaseolus vulgaris cv Black Valentine) the four possible pairs of satellite RNA molecules, one member of each pair having the wild-type sTRSV RNA sequence and the other that of the replicating mutant 51AG/212CU, with each sequence provided as the unit circular or linear form. The relative amounts of wild-type and mutant satellite RNA sequence recovered from progeny virions reflected their relative abundances in the inoculum without regard to whether the sequence was supplied as a linear or a circular molecule. These results are consistent with models for the replication of the satellite RNA in which a circular form of the satellite RNA is a template for rolling circle transcription or is otherwise a replication intermediate or is readily converted to an intermediate. We also show that a circular form of a nonaccumulating satellite RNA mutant induced an increase in a satellite RNA that is endogenous to some tobacco ringspot virus virion preparations, as demonstrated previously for the linear form.
烟草环斑病毒的一种小卫星RNA（sTRSV RNA）在复制过程中产生单位长度和重复序列的环状和线性分子、线性多聚体。连接多聚体和环状RNA中单位卫星RNA序列的磷酸二酯键在环状分子中能抵抗碱催化的切割，但在线性二聚体中则不能。我们推测，多聚体卫星RNA的连接在多核糖核苷酸链合成过程中形成，而环状RNA的连接则是由一种连接反应产生的，该反应引入了一个封闭连接点2'-羟基的基团。为了测试线性和环状卫星RNA启动复制的相对有效性，我们将四对可能的卫星RNA分子接种到菜豆（菜豆品种黑瓦伦丁）上，每对中的一个成员具有野生型sTRSV RNA序列，另一个具有复制突变体51AG/212CU的序列，每个序列都以单位环状或线性形式提供。从子代病毒粒子中回收的野生型和突变体卫星RNA序列的相对量反映了它们在接种物中的相对丰度，而不考虑该序列是以线性还是环状分子形式提供的。这些结果与卫星RNA复制模型一致，在该模型中，卫星RNA的环状形式是滚环转录的模板，或者是复制中间体，或者很容易转化为中间体。我们还表明，一种非积累性卫星RNA突变体的环状形式诱导了一些烟草环斑病毒病毒粒子制剂中内源性卫星RNA的增加，正如之前对线性形式所证明的那样。
