Li Ruojiao, Zhang Ru, Zhang Lu, Zou Jiajun, Xing Qiang, Dou Huaiqian, Hu Xiaoli, Zhang Lingling, Wang Ruijia, Bao Zhenmin
Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
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 Jun;44(2):611-21. doi: 10.1016/j.fsi.2015.03.036. Epub 2015 Apr 1.
Rel/NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) genes are evolutionarily conserved and play a pivotal role in several physiological events. They have been extensively studied from various species, including both vertebrates and invertebrates. However, the Rel/NF-κB genes have not been systematically characterized in bivalves. In this study, we identified and characterized PyNF-κB and PyRel in the Yesso scallop (Patinopecten yessoensis). Phylogenetic and protein structural analyses were conducted to determine the identities and evolutionary relationships of Rel/NF-κB genes in Yesso scallop. Compared with the Rel/NF-κB genes from vertebrate species, the PyNF-κB and PyRel are relatively conserved in their structural features, but there were no paralogs found in P. yessoensis or other invertebrates. To gain insights into the roles of Rel/NF-κB genes during the innate immune response in scallop, quantitative real-time PCR was used to investigate the expression profiles of these genes at different developmental stages, in healthy adult tissues and in the hemolymph after bacterial infection with Micrococcus luteus and Vibrio anguillarum. The real-time PCR results indicated the abundance of PyNF-κB in the first four embryonic stages, including oocytes, fertilized eggs, morulae and blastulae. By contrast, PyRel was abundantly expressed in blastulae, trochophores and D-shaped larvae. In adult scallops, PyNF-κB and PyRel were ubiquitously expressed in most healthy tissues and highly expressed in most of the immune related tissues. Both genes were significantly up-regulated during the acute phase (3 h) after infection with Gram-positive (M. luteus) and negative (V. anguillarum) bacteria, while the much higher expression level of PyNF-κB suggested the involvement of the extra immune deficiency (IMD)-like pathway against the Gram-negative bacterial infection. The complex pattern of Rel/NF-κB induced expression suggested that PyNF-κB and PyRel both have specific and cooperative roles in the acute immune responses to bacterial infection.
Rel/NF-κB（活化B细胞的核因子κ轻链增强子）基因在进化上是保守的，在多种生理过程中起关键作用。人们已经对包括脊椎动物和无脊椎动物在内的各种物种进行了广泛研究。然而，双壳贝类中的Rel/NF-κB基因尚未得到系统鉴定。在本研究中，我们在虾夷扇贝（Patinopecten yessoensis）中鉴定并表征了PyNF-κB和PyRel。通过系统发育和蛋白质结构分析来确定虾夷扇贝中Rel/NF-κB基因的特性和进化关系。与脊椎动物物种的Rel/NF-κB基因相比，PyNF-κB和PyRel在结构特征上相对保守，但在虾夷扇贝或其他无脊椎动物中未发现旁系同源基因。为了深入了解Rel/NF-κB基因在扇贝先天免疫反应中的作用，我们使用定量实时PCR来研究这些基因在不同发育阶段、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淋巴中的表达谱。实时PCR结果表明，PyNF-κB在前四个胚胎阶段（包括卵母细胞、受精卵、桑椹胚和囊胚）中含量丰富。相比之下，PyRel在囊胚、担轮幼虫和D形幼虫中大量表达。在成年扇贝中，PyNF-κB和PyRel在大多数健康组织中普遍表达，并在大多数免疫相关组织中高表达。在用革兰氏阳性菌（藤黄微球菌）和阴性菌（鳗弧菌）感染后的急性期（3小时），这两个基因均显著上调，而PyNF-κB更高的表达水平表明额外免疫缺陷（IMD）样途径参与了针对革兰氏阴性菌感染的免疫反应。Rel/NF-κB诱导表达的复杂模式表明，PyNF-κB和PyRel在对细菌感染的急性免疫反应中均具有特定且协同的作用。
