College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China; University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, Guangzhou, China.
Fish Shellfish Immunol. 2022 Aug;127:956-964. doi: 10.1016/j.fsi.2022.06.053. Epub 2022 Jun 25.
Growing evidences have demonstrated that multiple TRIM (tripartite motif) proteins exert critical roles in host defense against different microbial pathogens. Although mammalian TRIM21 has been reported to function as an important regulatory factor in antiviral immune and inflammatory response, the role of fish TRIM21 against virus infection still remains largely unknown. In the present study, we investigated the characteristics of TRIM21 gene (EcTRIM21) from orange spotted grouper (Epinephelus coioides). The full-length EcTRIM21 cDNA encoded a 557 amino acid peptide with 92.1% and 31.14% identity with giant grouper (Epinephelus lanceolatus) and human (Homo sapiens), respectively. EcTRIM21 contained four conserved domains, including RING, B-Box, PRY and SPRY domain. EcTRIM21 expression was significantly up-regulated in response to Singapore grouper iridovirus (SGIV) and red-spotted grouper nervous necrosis virus (RGNNV) infection, suggesting that EcTRIM21 might be involved in host defense against fish virus infections. Subcellular localization showed that EcTRIM21 were distributed in the cytoplasm in a punctate manner. Overexpression of EcTRIM21 in vitro significantly inhibited RGNNV and SGIV replication, as evidenced by the decreased severity of cytopathic effect (CPE) and the reduced expression levels of viral core genes. Consistently, knockdown of EcTRIM21 by small interfering RNA (siRNA) promoted the replication of RGNNV and SGIV in vitro. Furthermore, EcTRIM21 overexpression increased both interferon (IFN) and interferon stimulated response element (ISRE) promoter activities. In addition, the transcription levels of IFN signaling related molecules were positively regulated by EcTRIM21 overexpression. Together, our data demonstrated that fish TRIM21 exerted antiviral activity against fish viruses through positive regulation of host interferon response.
越来越多的证据表明，多种 TRIM（三肽基结构域）蛋白在宿主抵抗不同微生物病原体的防御中发挥关键作用。虽然哺乳动物 TRIM21 已被报道在抗病毒免疫和炎症反应中作为重要的调节因子发挥作用，但鱼类 TRIM21 对病毒感染的作用仍知之甚少。在本研究中，我们研究了橙色斑点石斑鱼（Epinephelus coioides）TRIM21 基因（EcTRIM21）的特征。全长 EcTRIM21 cDNA 编码一个 557 个氨基酸的肽，与巨石斑鱼（Epinephelus lanceolatus）和人类（Homo sapiens）的同源性分别为 92.1%和 31.14%。EcTRIM21 包含四个保守结构域，包括 RING、B-Box、PRY 和 SPRY 结构域。EcTRIM21 的表达在受到新加坡石斑鱼虹彩病毒（SGIV）和红鳍东方鲀神经坏死病毒（RGNNV）感染后显著上调，表明 EcTRIM21 可能参与宿主对鱼类病毒感染的防御。亚细胞定位显示 EcTRIM21 以点状方式分布在细胞质中。体外过表达 EcTRIM21 显著抑制 RGNNV 和 SGIV 的复制，表现为细胞病变效应（CPE）严重程度降低和病毒核心基因表达水平降低。一致地，通过小干扰 RNA（siRNA）敲低 EcTRIM21 促进了 RGNNV 和 SGIV 在体外的复制。此外，EcTRIM21 的过表达增加了干扰素（IFN）和干扰素刺激反应元件（ISRE）启动子的活性。此外，EcTRIM21 的过表达正向调节 IFN 信号相关分子的转录水平。总之，我们的数据表明，鱼类 TRIM21 通过正向调节宿主干扰素反应对鱼类病毒发挥抗病毒活性。
