Jovel Juan, Preiss Werner, Jeske Holger
Department of Molecular Biology and Plant Virology, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
Virus Res. 2007 Dec;130(1-2):63-70. doi: 10.1016/j.virusres.2007.05.018. Epub 2007 Jun 29.
Weeds of the genus Sida collected in Brazil have harbored several geminiviruses persistently over decades of vegetative propagation. They serve as cradles for new geminiviruses originating from pseudorecombination (reassortment) or molecular recombination, as has been exemplified by Sida micrantha mosaic-associated viruses (SimMV). One of such viruses has developed recently and naturally by recombination between a DNA A and a DNA B of different ancestors. We used two-dimensional gel electrophoresis and hybridization to visualize viral DNA intermediates in mixed infections as well as after transfer of single viruses into test plants. DNA intermediates which indicate multitasking in replication (rolling circle and recombination-dependent replication) were readily detected in all cases. A conspicuous increase in multimerization of circular single-stranded (ss) DNA could be attributed to the recently recombined geminivirus, suggesting poor adaptation to the host and/or inefficient gene regulation. Consequences of the accumulation of multimeric ssDNA were analyzed using nucleoprotein particle purification and electron microscopy. SimMV nucleoprotein exhibited pleomorphic structures in addition to the typical twin particles. This report provides the first analysis of DNA intermediates of an arising geminivirus.
在巴西采集的黄花稔属杂草在数十年的营养繁殖过程中一直携带着多种双生病毒。它们是源自假重组（重配）或分子重组的新型双生病毒的摇篮，小花黄花稔花叶相关病毒（SimMV）就是一个例证。其中一种病毒最近通过不同祖先的DNA A和DNA B之间的重组自然形成。我们使用二维凝胶电泳和杂交技术来观察混合感染以及将单一病毒转移到测试植物后病毒DNA中间体的情况。在所有情况下都很容易检测到表明复制过程中具有多种功能（滚环复制和依赖重组的复制）的DNA中间体。环状单链（ss）DNA多聚化的显著增加可能归因于最近重组的双生病毒，这表明对宿主的适应性较差和/或基因调控效率低下。使用核蛋白颗粒纯化和电子显微镜分析了多聚体ssDNA积累的后果。除了典型的孪生颗粒外，SimMV核蛋白还呈现出多形结构。本报告首次分析了新兴双生病毒的DNA中间体。
