VP23R of Infectious Spleen and Kidney Necrosis Virus Mediates Formation of Virus-Mock Basement Membrane To Provide Attaching Sites for Lymphatic Endothelial Cells
VP23R of Infectious Spleen and Kidney Necrosis Virus Mediates Formation of Virus-Mock Basement Membrane To Provide Attaching Sites for Lymphatic Endothelial Cells
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DOI：
10.1128/jvi.00990-10
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发表时间：
2010-09
影响因子：
5.4
通讯作者：
Xiaopeng Xu;S. Weng;Ting Lin;Junliang Tang;Lichao Huang;Jing Wang;Xiaoqiang Yu;Ling Lu;Zhijian Huang;Jianguo He
中科院分区：
文献类型：
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作者：
Xiaopeng Xu;S. Weng;Ting Lin;Junliang Tang;Lichao Huang;Jing Wang;Xiaoqiang Yu;Ling Lu;Zhijian Huang;Jianguo He
摘要在虹膜病毒科巨细胞病毒属的所有成员中都发现了编码层粘连蛋白样蛋白的开放阅读框架(ORF)。这是首次发现传染性脾肾坏死病毒(ISKNV)的ORF23R编码的VP23R蛋白，ISKNV是巨细胞病毒这些基因的一员。覆盖ISKNV基因组坐标19547至22273的VP23RmRNA在主要衣壳蛋白之前转录。免疫荧光分析表明，VP23R表达于ISKNV感染细胞的质膜上，不能作为病毒包膜蛋白。VP23R的第292至576位残基与层粘连蛋白γ1III2-6片段同源，该片段覆盖了Nidgen结合部位。免疫沉淀实验表明VP23R可与Nidogen-1相互作用，免疫组织化学显示Nidogen-1定位于感染细胞的外膜。电子显微镜显示，感染细胞表面形成了一层病毒样基底膜(VMBM)，并在VMBM上附着了一层内皮细胞(ECs)。VMBM含有VP23R和Nidogen-1，但不含IV型胶原。附着的内皮细胞被鉴定为淋巴管内皮细胞，具有细胞间连接重叠的独特特征，并可用特异性淋巴标志物Prox-1的抗体进行免疫组化染色。这种感染迹象从未在病毒中被描述过。阐明巨细胞病毒感染细胞表面LECs的功能可能有助于研究巨细胞病毒的致病机制，也可能对淋巴管生成和基底膜功能的研究具有重要意义。
ABSTRACT Putative open reading frames (ORFs) encoding laminin-like proteins are found in all members of the genus Megalocytivirus, family Iridoviridae. This is the first study that identified the VP23R protein encoded by ORF23R of the infectious spleen and kidney necrosis virus (ISKNV), a member of these genes of megalocytiviruses. The VP23R mRNA covering the ISKNV genomic coordinates 19547 to 22273 was transcribed ahead of the major capsid protein. Immunofluorescence analysis demonstrated that VP23R was expressed on the plasma membrane of the ISKNV-infected cells and could not be a viral envelope protein. Residues 292 to 576 of VP23R are homologous to the laminin γ1III2-6 fragment, which covers the nidogen-binding site. An immunoprecipitation assay showed that VP23R could interact with nidogen-1, and immunohistochemistry showed that nidogen-1 was localized on the outer membrane of the infected cells. Electron microscopy showed that a virus-mock basement membrane (VMBM) was formed on the surface of the infected cells and a layer of endothelial cells (ECs) was attached to the VMBM. The VMBM contained VP23R and nidogen-1 but not collagen IV. The attached ECs were identified as lymphatic endothelial cells (LECs), which have unique feature of overlapping intercellular junctions and can be stained by immunohistochemistry using an antibody against a specific lymphatic marker, Prox-1. Such infection signs have never been described in viruses. Elucidating the functions of LECs attached to the surface of the infected cells may be useful for studies on the pathogenic mechanisms of megalocytiviruses and may also be important for studies on lymphangiogenesis and basement membrane functions.