Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410017, China; Department of Biology, Zhaoqing University, Zhaoqing, 526061, China.
Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410017, China.
Fish Shellfish Immunol. 2020 Sep;104:592-604. doi: 10.1016/j.fsi.2020.06.022. Epub 2020 Jun 23.
Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a multifunctional adaptor protein primarily involved in both bacterial defense and antiviral immunity in living organisms. However, the knowledge on TRAF3 in blunt snout bream (Megalobrama amblycephala), a freshwater fish with economic values, remained unclear. In the present study, we identified and characterized successfully Traf3 gene from M. amblycephala (maTraf3). The maTraf3 cDNA contained a 1722 bp open reading frame that encoded a protein of 573 amino acid residues. The deduced amino acid sequence comprised of a RING finger domain, two zinc finger motifs, a coiled-coil region and a MATH domain. Analysis of the transcriptional patterns of maTraf3 revealed that it was ubiquitously distributed in various tissues tested from M. amblycephala, with the abundance of expression in spleen and muscle. Following a challenge with Aeromonas hydrophila and lipopolysaccharide stimulation, the expression of maTraf3 was strongly enhanced at different time points in vitro and in vivo. MaTRAF3 was identified as a cytosolic protein and suggested to form aggregates or be associated with vesicles scattering in the cytoplasm. NF-κB transcription was activated by maTraf3 in reporter assay. The overexpression of maTraf3 produced high levels of pro-inflammatory cytokines such as IL-1β, IL-6, IL-8 and TNF-α, implying its immune-regulatory role in M. amblycephala. Taken together, our results obtained in this study demonstrated the crucial role of maTraf3 in mediating host innate immune response to pathogen invasion via NF-κB signaling pathway, which might indicate a novel therapeutic approach to combat bacterial infection in fish.
肿瘤坏死因子受体相关因子 3（TRAF3）是一种多功能衔接蛋白，主要参与生物体内的细菌防御和抗病毒免疫。然而，关于淡水鱼类团头鲂（Megalobrama amblycephala）中 TRAF3 的知识尚不清楚。本研究中，我们成功地从团头鲂中鉴定和表征了 Traf3 基因（maTraf3）。maTraf3 cDNA 含有 1722 bp 的开放阅读框，编码 573 个氨基酸残基的蛋白质。推导的氨基酸序列包含一个 RING 指结构域、两个锌指基序、一个卷曲螺旋区和一个 MATH 结构域。分析 maTraf3 的转录模式表明，它在各种组织中广泛分布，在脾脏和肌肉中的表达丰度最高。在体外和体内受到嗜水气单胞菌和脂多糖刺激后，maTraf3 的表达在不同时间点均显著增强。MaTRAF3 被鉴定为一种胞质蛋白，表明其在细胞质中形成聚集体或与散布的囊泡相关。maTraf3 在报告基因检测中激活了 NF-κB 转录。maTraf3 的过表达产生了高水平的促炎细胞因子，如 IL-1β、IL-6、IL-8 和 TNF-α，表明其在团头鲂中具有免疫调节作用。综上所述，本研究结果表明，maTraf3 通过 NF-κB 信号通路在介导宿主固有免疫反应对抗病原体入侵方面发挥着重要作用，这可能为鱼类细菌性感染的治疗提供新的方法。
