State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan, China.
PLoS One. 2012;7(8):e43033. doi: 10.1371/journal.pone.0043033. Epub 2012 Aug 13.
The complete genome of Rana grylio virus (RGV) was sequenced and analyzed recently, which revealed that RGV 50 L had homologues in many iridoviruses with different identities; however, the characteristics and functions of 50 L have not been studied yet.
METHODOLOGY/PRINCIPAL FINDINGS: We cloned and characterized RGV50L, and revealed 50 L functions in virus assembly and gene regulation. 50 L encoded a 499-amino acid structural protein of about 85 kDa in molecular weight and contained a nuclear localization signal (NLS) and a helix- extension-helix motif. Drug inhibition assay demonstrated that 50 L was an immediate-early (IE) gene. Immuno-fluorescence assay revealed that 50 L appeared early and persisted in RGV-infected cells following two distribution patterns. One pattern was that 50 L exhibited a cytoplasm-nucleus- viromatrix distribution pattern, and mutagenesis of the NLS motif revealed that localization of 50 L in the nucleus was NLS-dependent; the other was that 50 L co-localized with viral matrix which plays important roles in virus assembly and the life circle of viruses.
CONCLUSIONS/SIGNIFICANCE: RGV 50L is a novel iridovirus IE gene encoded structural protein which plays important roles in virus assembly.
最近，对蛙病毒（Rana grylio virus，RGV）的全基因组进行了测序和分析，结果表明 RGV 的 50L 与多种虹彩病毒具有同源性，但其身份不同；然而，50L 的特征和功能尚未得到研究。
方法/主要发现：我们克隆并鉴定了 RGV50L，并揭示了 50L 在病毒组装和基因调控中的功能。50L 编码一个分子量约为 85kDa 的 499 个氨基酸的结构蛋白，包含一个核定位信号（NLS）和一个螺旋-延伸-螺旋基序。药物抑制实验表明，50L 是一个早期基因（IE）。免疫荧光实验显示，50L 在 RGV 感染细胞中早期出现，并呈现两种分布模式。一种模式是 50L 表现出细胞质-细胞核-病毒基质的分布模式，NLS 基序的突变表明 50L 在细胞核中的定位是 NLS 依赖性的；另一种是 50L 与病毒基质共定位，病毒基质在病毒组装和病毒生命周期中发挥重要作用。
结论/意义：RGV 50L 是一种新型虹彩病毒 IE 基因编码的结构蛋白，在病毒组装中发挥重要作用。
