Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521, USA.
Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521, USA.
Virology. 2015 Sep;483:163-73. doi: 10.1016/j.virol.2015.04.012. Epub 2015 May 15.
In this study, we assembled an Agrobacterium-based transient expression system for the ectopic expression of Satellite tobacco mosaic virus (STMV) (+) or (-) transcripts and their biological activity was confirmed when Nicotiana benthamiana plants were co-expressed with helper Tobacco mosaic virus replicase. Characterization of STMV in the presence and absence of its HV revealed: (i) HV-dependent expression of STMV (+) in N. benthamiana, but not in N. tabacum, generated a replication-deficient but translation and encapsidation competent variant lacking the highly conserved 3' 150 nucleotides (nt) (STMVΔ150); (ii) mutational analysis demonstrated that a conserved 3' stem-loop structure in wild type and STMVΔ150 located between nt 874 and 897 is essential for translation of CP; (iii) helper virus-independent expression of CP from wt STMV was competent for the assembly of empty aberrant virion-like particles; whereas, CP translated from STMVΔ150 resulted in disorganized CP aggregates suggesting a role for the 3'tRNA-like structure in STMV assembly.
在这项研究中，我们组装了一个基于农杆菌的瞬时表达系统，用于异位表达卫星烟草花叶病毒（STMV）的（+）或（-）转录本，当拟南芥植物与辅助烟草花叶病毒复制酶共表达时，其生物活性得到了证实。在存在和不存在其 HV 的情况下对 STMV 的表征揭示了：（i）HV 依赖性表达在 N. benthamiana 中，但不在 N. tabacum 中，产生了一种复制缺陷但翻译和封装有效的变体，缺乏高度保守的 3'150 个核苷酸（nt）（STMVΔ150）；（ii）突变分析表明，野生型和 STMVΔ150 中位于 nt 874 和 897 之间的保守 3'茎环结构对于 CP 的翻译是必不可少的；（iii）wt STMV 从辅助病毒独立表达的 CP 能够组装空的异常病毒样颗粒；然而，从 STMVΔ150 翻译的 CP 导致 CP 聚集体的紊乱，这表明 3'tRNA 样结构在 STMV 组装中起作用。
