Wang Jing, Wang Ruijia, Wang Shuyue, Zhang Mengran, Ma Xiaoli, Liu Pingping, Zhang Meiwei, Hu Xiaoli, Zhang Lingling, Wang Shi, Bao Zhenmin
Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
Fish Shellfish Immunol. 2015 Nov;47(1):545-55. doi: 10.1016/j.fsi.2015.09.050. Epub 2015 Oct 3.
The tumor necrosis factor (TNF) receptor associated factors (TRAFs) are the major signal transducers for the TNF receptor superfamily and the interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) superfamily, which regulate a variety of cellular activities and innate immune responses. TRAF genes have been extensively studied in various species, including vertebrates and invertebrates. However, as one of the key component of NF-κB pathway, TRAF genes have not been systematically characterized in marine invertebrates. In this study, we identified and characterized five TRAF genes, PyTRAF2, PyTRAF3, PyTRAF4, PyTRAF6 and PyTRAF7, in the Yesso scallop (Patinopecten yessoensis). Phylogenetic and protein structural analyses were conducted to determine their identities and evolutionary relationships. In comparison with the TRAF genes from vertebrate species, the structural features were all relatively conserved in the PyTRAF genes. To gain insights into the roles of TRAF genes during scallop innate immune responses, quantitative real-time PCR was used to investigate the expression profiles in the different stages of scallop development, in the healthy adult tissues, and in the hemocytes after bacterial infection with Micrococcus luteus and Vibrio anguillarum. Based on the qRT-PCR analysis, the expression of most of the PyTRAFs was significantly induced in the acute phases (3-6 h) after infection with Gram-positive (M. luteus) and Gram-negative (V. anguillarum) bacteria, and many more dramatic changes in PyTRAFs expression were observed after V. anguillarum challenge. Notably, the strong response in the up-regulation of PyTRAF6 post-bacterial challenge was distinct from that previously reported in scallops and crabs but was similar to that of other shellfish, Echinodermata and even teleost fish. The high level expressions of PyTRAFs in the hemocytes and the gill, and their specific expression patterns after challenges provide insights into the versatile roles and responses of TRAFs in the innate immune system against Gram-negative bacterial pathogens in bivalves.
肿瘤坏死因子（TNF）受体相关因子（TRAFs）是TNF受体超家族以及白细胞介素-1受体/Toll样受体（IL-1R/TLR）超家族的主要信号转导分子，它们调节多种细胞活动和先天免疫反应。TRAF基因已在包括脊椎动物和无脊椎动物在内的各种物种中得到广泛研究。然而，作为核因子κB（NF-κB）信号通路的关键组成部分之一，TRAF基因在海洋无脊椎动物中尚未得到系统的表征。在本研究中，我们在虾夷扇贝（Patinopecten yessoensis）中鉴定并表征了五个TRAF基因，即PyTRAF2、PyTRAF3、PyTRAF4、PyTRAF6和PyTRAF7。进行了系统发育和蛋白质结构分析以确定它们的身份和进化关系。与脊椎动物物种的TRAF基因相比，PyTRAF基因的结构特征都相对保守。为了深入了解TRAF基因在扇贝先天免疫反应中的作用，我们使用定量实时PCR来研究其在扇贝发育的不同阶段、健康成体组织以及在用藤黄微球菌和鳗弧菌进行细菌感染后的血细胞中的表达谱。基于qRT-PCR分析，大多数PyTRAFs的表达在感染革兰氏阳性菌（藤黄微球菌）和革兰氏阴性菌（鳗弧菌）后的急性期（3-6小时）显著诱导，并且在鳗弧菌攻击后观察到PyTRAFs表达的更多显著变化。值得注意的是，细菌攻击后PyTRAF6上调的强烈反应与先前在扇贝和螃蟹中报道的不同，但与其他贝类、棘皮动物甚至硬骨鱼相似。PyTRAFs在血细胞和鳃中的高水平表达以及它们在攻击后的特异性表达模式，为TRAFs在双壳贝类针对革兰氏阴性细菌病原体的先天免疫系统中的多种作用和反应提供了见解。
