Host-dependent recombination of a Tomato bushy stunt virus coat protein mutant yields truncated capsid subunits that form virus-like complexes which benefit systemic spread
Host-dependent recombination of a Tomato bushy stunt virus coat protein mutant yields truncated capsid subunits that form virus-like complexes which benefit systemic spread
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DOI：
10.1006/viro.2002.1714
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发表时间：
2002-12-20
期刊：
影响因子：
3.7
通讯作者：
Scholthof, HB
中科院分区：
文献类型：
--
作者：
Desvoyes, B;Scholthof, HB
本研究考察了番茄丛矮病毒 (TBSV) 外壳蛋白 (CP) 及其相应的 RNA 对植物全身感染的贡献。与缺乏 CP 基因 5'-半部分的突变体获得的结果相比，另一个突变体中这些 CP-RNA 序列的存在有利于本塞姆氏烟草的 TBSV 感染，尽管通过引入小的框外删除消除了野生型 CP 表达。对与这种 CP 移码缺失突变体建立的快速感染相关的病毒 RNA 进行的 RT-PCR 显示，植物体内重组为后代提供了表达截短 CP (tCP) 的能力，该截短 CP (tCP) 的 N-近端 30 个残基从 66 个氨基酸的 RNA 结合结构域中删除。随后的生化特征揭示了大核糖核蛋白复合物的存在，该复合物被证明含有病毒RNA以及类似于38-kDa tCP。纯化复合物的电子显微镜检查显示，与野生型 TBSV 颗粒相比，颗粒状结构的大小和形状不均匀。用含有 tCP 的核糖核蛋白复合物接种辣椒会导致快速全身感染，类似于野生型 TBSV 引起的感染。相比之下，在辣椒中由原始 CP 移码缺失突变体转录物建立的感染仅限于接种的叶子，并且不会产生能够系统感染该宿主的重组体。总之，TBSV 具有形成替代病毒体样结构的灵活性，即使大部分 RNA 结合结构域从 CP 中删除；产生含有 tCP 的颗粒状结构的突变体比那些缺乏 CP 表达的突变体更能有效地传播病毒；产生替代 tCP-RNA 复合物的重组事件是宿主依赖性的。 (C) 2002 年爱思唯尔科学（美国）。
This study examined the contribution of the Tomato bushy stunt virus (TBSV) coat protein (CP) and its corresponding RNA to systemic infection of plants. Compared to results obtained with a mutant lacking the 5'-half of the CP gene, the presence of those CP-RNA sequences in another mutant benefited TBSV infection on Nicotiana benthamiana even though wild-type CP expression was eliminated by introduction of a small out-of-frame deletion. RT-PCR of viral RNA associated with rapid infections established by this CP frameshift deletion mutant revealed that in planta recombination had provided the progeny with the ability to express a truncated CP (tCP) with a block of N-proximal 30 residues deleted from the 66 amino acid RNA-binding domain. Subsequent biochemical characterizations revealed the presence of large ribonucleoprotein complexes that were shown to contain viral RNA as well as the similar to38-kDa tCP. Electron microscopic examination of purified complexes showed particle-like structures that were nonuniform in size and shape compared to wild-type TBSV particles. Inoculation of pepper with the tCP-containing ribonucleoprotein complexes resulted in a rapid systemic infection similar to that caused by wild-type TBSV. In contrast, infections established in pepper by the original CP frameshift deletion mutant transcripts were restricted to inoculated leaves and did not yield recombinants capable of systemically infecting this host, In summary, TBSV possesses the flexibility to form alternative virion-like structures even if a substantial portion of the RNA-binding domain is deleted from the CP; mutants producing the tCP-containing particle-like structures are more effective for virus spread than those devoid of CP expression; and recombination events to produce the alternative tCP-RNA complexes are host-dependent. (C) 2002 Elsevier Science (USA).