Castle E, Nowak T, Leidner U, Wengler G, Wengler G
Virology. 1985 Sep;145(2):227-36. doi: 10.1016/0042-6822(85)90156-4.
Cell-associated flaviviruses contain the two membrane proteins V3 and NV2 besides the viral core protein V2 whereas extracellular viruses do contain V2 protein and the two membrane proteins V3 and V1. Since the V1 protein could not be detected in infected cells it has been suggested that V1 is generated from NV2 by proteolytic cleavage during the release of virus from cells (D. Shapiro, W. E. Brandt, and P. K. Russell (1972), Virology 50, 906-911). We have isolated the viral structural proteins V1, V2, and NV2 from the flavivirus West Nile virus and determined their amino-terminal amino acid sequences and amino acid sequences of peptides derived from these proteins. We have also transcribed parts of the viral genome into cDNA and cloned and sequenced this cDNA. The analyses of the protein structure of V1, V2, and NV2 together with the determination of the amino-terminal sequence of V3 (data not shown) have allowed us to identify the nucleotide region coding for the structural proteins V2, NV2, and V1. The primary structure of this nucleotide sequence is presented in this report. The data show that the amino terminus of the viral core protein V2 is followed by the amino termini of the proteins NV2, V1, and V3, respectively. These data for the first time identify the exact order of all structural proteins of a flavivirus identified so far. Our data strongly support the above-mentioned hypothesis that V1 is derived from NV2 by proteolytic cleavage and furthermore indicate that V1 represents the nonglycosylated carboxy-terminal part of NV2 which contains those sequences which anchor NV2 in the viral membrane. A working hypothesis is presented in which two species of cellular enzymes, signalase(s) removing signal sequences and enzymes involved in cleaving polyproteins after a pair of basic amino acids, do generate the proteins V2, NV2, and V1 from the growing peptide chain synthesized during translation of the 42 S genome RNA which functions as mRNA for these proteins.
与细胞相关的黄病毒除了病毒核心蛋白V2外，还含有两种膜蛋白V3和NV2，而细胞外病毒确实含有V2蛋白以及两种膜蛋白V3和V1。由于在感染细胞中未检测到V1蛋白，因此有人提出V1是在病毒从细胞释放过程中通过蛋白水解切割从NV2产生的（D. Shapiro、W. E. Brandt和P. K. Russell，1972年，《病毒学》50卷，906 - 911页）。我们从黄病毒西尼罗河病毒中分离出了病毒结构蛋白V1、V2和NV2，并确定了它们的氨基末端氨基酸序列以及源自这些蛋白的肽段的氨基酸序列。我们还将病毒基因组的部分片段转录成cDNA，并对该cDNA进行了克隆和测序。对V1、V2和NV2的蛋白质结构分析以及V3氨基末端序列的测定（数据未显示）使我们能够确定编码结构蛋白V2、NV2和V1的核苷酸区域。本报告展示了该核苷酸序列的一级结构。数据表明，病毒核心蛋白V2的氨基末端之后分别是蛋白NV2、V1和V3的氨基末端。这些数据首次确定了迄今为止所鉴定的黄病毒所有结构蛋白的确切顺序。我们的数据有力地支持了上述假设，即V1是通过蛋白水解切割从NV2衍生而来，并且进一步表明V1代表NV2的非糖基化羧基末端部分，其中包含将NV2锚定在病毒膜中的那些序列。我们提出了一个工作假设，即两种细胞酶，去除信号序列的信号酶以及在一对碱性氨基酸后切割多蛋白的酶，确实从作为这些蛋白mRNA的42S基因组RNA翻译过程中合成的不断增长的肽链产生蛋白V2、NV2和V1。
