Nucleotide sequence and genome organization of grapevine leafroll-associated virus-2 are similar to beet yellows virus, the closterovirus type member.
Nucleotide sequence and genome organization of grapevine leafroll-associated virus-2 are similar to beet yellows virus, the closterovirus type member.
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葡萄卷叶相关病毒-2 的核苷酸序列和基因组结构与线形病毒类型成员甜菜黄化病毒相似。
DOI：
10.1099/0022-1317-79-5-1289
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
D. Gonsalves
中科院分区：
文献类型：
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作者：
H Y Zhu;K S Ling;J R McFerson;D. Goszczynski;D. Gonsalves
对葡萄叶相关closterovirus-2 （GLRaV-2）除5′末端外的全基因组进行了克隆和测序。该序列包括9个开放阅读框（orf），其中在5‘到3’方向上，一个不完整的ORF1a编码一个假定的病毒多蛋白，8个orf分别编码52 kDa （ORF1b）、6 kDa （ORF2）、65 kDa （ORF3）、63 kDa （ORF4）、25 kDa （ORF5）、22 kDa （ORF6）、19 kDa （ORF7）和24 kDa （ORF8）蛋白，以及216个3'未翻译区核苷酸。一个不完整的ORF1a可能编码一个大的多蛋白，包含木瓜蛋白酶、甲基转移酶和解旋酶的保守结构域。ORF1b可能编码一种假定的依赖RNA的RNA聚合酶。ORF1b的表达可能通过+1核糖体移码机制，类似于其他的封闭型病毒。在glrav2中还发现了一个独特的基因阵列，该基因阵列在其他closterovirus中是保守的；它包括编码6kda小疏水蛋白、65kda热休克蛋白70、63kda功能未知蛋白、25kda外壳蛋白重复和22kda外壳蛋白的基因。ORF6 （22 kDa）为外壳蛋白基因，经大肠杆菌体内表达和免疫印迹进一步证实。系统发育分析表明，glrav2与甜菜黄病毒（BYV）、甜菜黄突病毒和柑橘tristeza病毒有密切的亲缘关系。到目前为止，glrav2是唯一一种与类群BYV型成员的基因组组织相匹配的clostervirus，因此可以明确地归类为clostervirus属的确定成员。
The entire genome of grapevine leafroll-associated closterovirus-2 (GLRaV-2), except the exact 5' terminus, was cloned and sequenced. The sequence encompasses nine open reading frames (ORFs) which include, in the 5' to 3' direction, an incomplete ORF1a encoding a putative viral polyprotein and eight ORFs that encode proteins of 52 kDa (ORF1b), 6 kDa (ORF2), 65 kDa (ORF3), 63 kDa (ORF4), 25 kDa (ORF5), 22 kDa (ORF6), 19 kDa (ORF7) and 24 kDa (ORF8) respectively, and 216 nucleotides of the 3' untranslated region. An incomplete ORF1a potentially encoded a large polyprotein containing the conserved domains characteristic of a papain-like protease, methyltransferase and helicase. ORF1b potentially encoded a putative RNA-dependent RNA polymerase. The expression of ORF1b may be via a +1 ribosomal frameshift mechanism, similar to other closteroviruses. A unique gene array, which is conserved in other closteroviruses, was also identified in GLRaV-2; it includes genes encoding a 6 kDa small hydrophobic protein, 65 kDa heat shock protein 70, 63 kDa protein of function unknown, 25 kDa coat protein duplicate and 22 kDa coat protein. Identification of ORF6 (22 kDa) as the coat protein gene was further confirmed by in vivo expression in E. coli and immunoblotting. Phylogenetic analysis comparing different genes of GLRaV-2 with those of other closteroviruses demonstrated a close relationship with beet yellows virus (BYV), beet yellow stunt virus and citrus tristeza virus. GLRaV-2 is the only closterovirus, so far, that matches the genome organization of the type member of the group, BYV, and thus can be unambiguously classified as a definitive member of the genus Closterovirus.