Okada Y
Department of Bioscience, Teikyo University, Utsunomiya, Japan.
Philos Trans R Soc Lond B Biol Sci. 1999 Mar 29;354(1383):569-82. doi: 10.1098/rstb.1999.0408.
Early in the development of molecular biology, TMV RNA was widely used as a mRNA [corrected] that could be purified easily, and it contributed much to research on protein synthesis. Also, in the early stages of elucidation of the genetic code, artificially produced TMV mutants were widely used and provided the first proof that the genetic code was non-overlapping. In 1982, Goelet et al. determined the complete TMV RNA base sequence of 6395 nucleotides. The four genes (130K, 180K, 30K and coat protein) could then be mapped at precise locations in the TMV genome. Furthermore it had become clear, a little earlier, that genes located internally in the genome were expressed via subgenomic mRNAs. The initiation site for assembly of TMV particles was also determined. However, although TMV contributed so much at the beginning of the development of molecular biology, its influence was replaced by that of Escherichia coli and its phages in the next phase. As recombinant DNA technology developed in the 1980s, RNA virus research became more detached from the frontier of molecular biology. To recover from this setback, a gene-manipulation system was needed for RNA viruses. In 1986, two such systems were developed for TMV, using full-length cDNA clones, by Dawson's group and by Okada's group. Thus, reverse genetics could be used to elucidate the basic functions of all proteins encoded by the TMV genome. Identification of the function of the 30K protein was especially important because it was the first evidence that a plant virus possesses a cell-to-cell movement function. Many other plant viruses have since been found to encode comparable 'movement proteins'. TMV thus became the first plant virus for which structures and functions were known for all its genes. At the birth of molecular plant pathology, TMV became a leader again. TMV has also played pioneering roles in many other fields. TMV was the first virus for which the amino acid sequence of the coat protein was determined and first virus for which cotranslational disassembly was demonstrated both in vivo and in vitro. It was the first virus for which activation of a resistance gene in a host plant was related to the molecular specificity of a product of a viral gene. Also, in the field of plant biotechnology, TMV vectors are among the most promising. Thus, for the 100 years since Beijerinck's work, TMV research has consistently played a leading role in opening up new areas of study, not only in plant pathology, but also in virology, biochemistry, molecular biology, RNA genetics and biotechnology.
在分子生物学发展早期，烟草花叶病毒（TMV）RNA被广泛用作一种易于纯化的信使核糖核酸（mRNA）[已修正]，对蛋白质合成研究贡献巨大。此外，在遗传密码阐明的早期阶段，人工制备的TMV突变体被广泛使用，并首次证明遗传密码是不重叠的。1982年，戈莱特等人确定了TMV RNA由6395个核苷酸组成的完整碱基序列。随后，四个基因（130K、180K、30K和外壳蛋白基因）可以定位在TMV基因组的精确位置上。此外，稍早之前就已明确，基因组内部的基因是通过亚基因组mRNA进行表达的。TMV颗粒组装的起始位点也已确定。然而，尽管TMV在分子生物学发展初期贡献巨大，但在下一阶段，其影响力被大肠杆菌及其噬菌体所取代。随着20世纪80年代重组DNA技术的发展，RNA病毒研究与分子生物学前沿渐行渐远。为了从这一挫折中恢复过来，RNA病毒需要一种基因操作体系。1986年，道森团队和冈田团队利用全长cDNA克隆为TMV开发了两种这样的体系。因此，反向遗传学可用于阐明TMV基因组编码的所有蛋白质的基本功能。鉴定30K蛋白的功能尤为重要，因为这是植物病毒具有细胞间移动功能的首个证据。此后发现许多其他植物病毒也编码类似的“移动蛋白”。TMV因此成为首个所有基因的结构和功能都已知晓的植物病毒。在分子植物病理学诞生之时，TMV再次成为引领者。TMV在许多其他领域也发挥了开创性作用。TMV是首个外壳蛋白氨基酸序列被确定的病毒，也是首个在体内和体外均证明存在共翻译解聚现象的病毒。它是首个宿主植物中抗性基因的激活与病毒基因产物分子特异性相关的病毒。此外，在植物生物技术领域，TMV载体是最具前景的载体之一。因此，自贝杰林克的研究工作开展100年来，TMV研究不仅在植物病理学领域，而且在病毒学、生物化学、分子生物学、RNA遗传学和生物技术等领域，始终在开拓新的研究领域方面发挥着引领作用。
