School of Marine Sciences, Sun Yat-sen University, Guangzhou, 510000, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou, 510000, China; Pearl River Estuary Marine Ecosystem Research Station, Ministry of Education, Zhuhai, 519000, China.
Estuarine Fisheries Research Institute of Doumen, Zhuhai, China.
Fish Shellfish Immunol. 2022 Aug;127:910-917. doi: 10.1016/j.fsi.2022.07.041. Epub 2022 Jul 19.
Autophagy-related gene 5 (Atg5), an essential component of autophagy machinery, is associated with innate immune responses. Here, the Atg5 of sea perch (Lateolabrax japonicus) (LjAtg5) was cloned and its role in regulating autophagy and interferon (IFN) response during red-spotted grouper nervous necrosis virus (RGNNV) infection was investigated. The LjAtg5 cDNA encoded a polypeptide of 275 amino acids with an APG5 domain, and had the closet genetic relationship with Micropterus salmoides Atg5. Autophagic detection showed LjAtg5 was conserved in inducing cell autophagy. Spatial expression analysis revealed LjAtg5 had a higher expression level in liver, brain, and kidney tissues of RGNNV-infected sea perch compared with the control group. In RGNNV-infected LJB cells, overexpression of LjAtg5 significantly increased the mRNA and protein levels of capsid protein, whereas knockdown of LjAtg5 led to the opposite effect, indicating LjAtg5 played a pro-viral role during RGNNV infection. Furthermore, dual luciferase reporter assay revealed LjAtg5 significantly suppressed the activation of sea perch type I IFN promoter in vitro, and overexpression of LjAtg5 strongly weaken the expression of genes related to the RIG-I-like receptors (RLRs) signaling pathway and IFN stimulated genes. These results suggested LjAtg5 promoted RGNNV infection by negatively regulating RLRs-IFN signaling pathway.
自噬相关基因 5（Atg5）是自噬机制的必需组成部分，与先天免疫反应有关。本研究克隆了海水鲈鱼（Lateolabrax japonicus）的 Atg5（LjAtg5），并研究了其在调控海水鲈鱼感染神经坏死病毒（RGNNV）后自噬和干扰素（IFN）反应中的作用。LjAtg5 cDNA 编码一个 275 个氨基酸的多肽，具有 APG5 结构域，与 Micropterus salmoides Atg5 的遗传关系最密切。自噬检测表明 LjAtg5 在诱导细胞自噬方面具有保守性。空间表达分析显示，与对照组相比，RGNNV 感染海水鲈鱼的肝脏、大脑和肾脏组织中 LjAtg5 的表达水平更高。在 RGNNV 感染的 LJB 细胞中，过表达 LjAtg5 显著增加了衣壳蛋白的 mRNA 和蛋白水平，而敲低 LjAtg5 则导致相反的效果，表明 LjAtg5 在 RGNNV 感染过程中发挥了促病毒作用。此外，双荧光素酶报告基因检测显示 LjAtg5 显著抑制了海水鲈鱼 I 型 IFN 启动子的体外激活，而过表达 LjAtg5 强烈抑制了 RLRs-IFN 信号通路和 IFN 刺激基因相关基因的表达。这些结果表明，LjAtg5 通过负调控 RLRs-IFN 信号通路促进 RGNNV 感染。
