Grouper Atg12 negatively regulates the antiviral immune response against Singapore grouper iridovirus (SGIV) infection
Grouper Atg12 negatively regulates the antiviral immune response against Singapore grouper iridovirus (SGIV) infection
复制标题
石斑鱼 Atg12 负调节针对新加坡石斑鱼虹彩病毒 (SGIV) 感染的抗病毒免疫反应
DOI：
10.1016/j.fsi.2019.08.037
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发表时间：
2019-10-01
影响因子：
4.7
通讯作者：
Qin, Qiwei
中科院分区：
文献类型：
--
作者：
Li, Chen;Yu, Yepin;Qin, Qiwei
自噬是一个进化上保守的、多步骤的溶酶体降解过程，用于维持细胞存活和体内平衡。一系列自噬相关基因（Atgs）参与了自噬途径。在哺乳动物中，越来越多的研究将一些atg的功能归因于它们在自噬体生物发生中的经典作用，例如对病原体的抗性。然而，人们对鱼类Atgs的功能知之甚少。本研究克隆并鉴定了橙斑石斑鱼（Epinephelus coioides）（Ecatg12）的atg12同源物。Ecatg12编码一个117个氨基酸的蛋白，与gourami （anabasteststudineus）和人类（Homo sapiens）分别具有94.0%和76.8%的同源性。感染新加坡石斑鱼虹膜病毒（SGIV）的细胞中Ecatg12的转录水平低于未感染细胞。荧光显微镜显示，EcAtg12定位于石斑鱼脾细胞的细胞质和细胞核中。EcAtg12的过表达显著增加了SGIV的复制，这可以通过增加细胞病变效应的严重程度、病毒基因的转录水平、病毒蛋白的水平和子代病毒的产量来证明。进一步的研究表明，EcAtg12过表达可降低干扰素（IFN）相关分子和促炎因子的表达水平，抑制IFN-3、干扰素刺激反应元件和核因子κ b的启动子活性。这些结果表明，EcAtg12通过下调抗病毒免疫应答，在SGIV复制中发挥重要作用。
Autophagy is an evolutionarily conserved, multi-step lysosomal degradation process used to maintain cell survival and homeostasis. A series of autophagy-related genes (Atgs) are involved in the autophagic pathway. In mammals, a growing number of studies have attributed functions to some Atgs that are distinct from their classical role in autophagosome biogenesis, such as resistance to pathogens. However, little is known about the functions of fish Atgs. In this study, we cloned and characterized an atg12 homolog from orange spotted grouper (Epinephelus coioides)(Ecatg12). Ecatg12 encodes a 117 amino acid protein that shares 94.0% and 76.8% identity with gourami (Anabastestudineus) and humans (Homo sapiens), respectively. The transcription level of Ecatg12 was lower in cells infected with Singapore grouper iridovirus (SGIV) than in non-infected cells. Fluorescence microscopy revealed that EcAtg12 localized in the cytoplasm and nucleus in grouper spleen cells. Overexpression of EcAtg12 significantly increased the replication of SGIV, as evidenced by increased severity of the cytopathic effect, transcription levels of viral genes, levels of viral proteins, and progeny virus yield. Further studies showed that EcAtg12 overexpression decreased the expression levels of interferon (IFN) related molecules and proinflammatory factors and inhibited the promoter activity of IFN-3, interferon-stimulated response element, and nuclear factor-kappa B. Together, these results demonstrate that EcAtg12 plays crucial roles in SGIV replication by downregulating antiviral immune responses.