School of Agriculture, Ludong University, Yantai, 264025, China.
School of Agriculture, Ludong University, Yantai, 264025, China.
Fish Shellfish Immunol. 2020 Jun;101:9-18. doi: 10.1016/j.fsi.2020.03.043. Epub 2020 Mar 23.
The nuclear factor-κB (NF-κB) signaling pathway plays a crucial role in regulating many physiological processes such as development, inflammation, apoptosis, cell proliferation, differentiation and immune responses. And the NF-κB/Rel family members were considered as the most important transcription factors in the NF-κB signaling pathway. In this study, we cloned a Rel homolog gene (named as CgRel2) from the Pacific oyster, Crassostrea gigas. The 2115-bp open reading frame (ORF) encodes 704 amino acids and CgRel2 possesses a conserved Rel Homology Domain (RHD) at the N-terminus. Phylogenetic analysis revealed that CgRel2 is most closely related to Pinctada fucata dorsal protein. CgRel2 transcripts are widely expressed in all tested tissues, with the highest expression observed in the labial palp and the gill. Moreover, the expression of CgRel2 is significantly upregulated after lipopolysaccharide (LPS), peptidoglycan (PGN), and polyinosinic-polycytidylic acid [poly(I:C)] challenge. CgRel2 transfection into human cell lines activated NF-κB, TNFα and oyster IL-17 (CgIL-17) reporter genes in a dose-dependent manner, while CgRel2 overexpression cannot induce ISRE (Interferon stimulation response element) reporter gene's transcriptional activity. Additionally, the results of co-immunoprecipitation showed that CgRel2 or CgRel1 could interact with oyster IκB1, IκB2 and IκB3 proteins strongly, which may be critical for the immune signaling transduction and the regulation of its immune functions. Together, these results suggest that CgRel2 could respond to pathogenic infection, participate in the immune signal transduction and activate NF-κB, TNFα and CgIL-17 reporter genes. Thus, CgRel2 could play an important role in the oyster immune system.
核因子-κB（NF-κB）信号通路在调节许多生理过程中起着至关重要的作用，如发育、炎症、细胞凋亡、细胞增殖、分化和免疫反应。NF-κB/Rel 家族成员被认为是 NF-κB 信号通路中最重要的转录因子。在这项研究中，我们从太平洋牡蛎（Crassostrea gigas）中克隆了一个 Rel 同源基因（命名为 CgRel2）。该基因的开放阅读框（ORF）长 2115bp，编码 704 个氨基酸，N 端具有保守的 Rel 同源结构域（RHD）。系统进化分析表明，CgRel2 与 Pinctada fucata 背蛋白最为密切相关。CgRel2 转录本在所有检测组织中广泛表达，其中在唇瓣和鳃中表达量最高。此外，在脂多糖（LPS）、肽聚糖（PGN）和聚肌苷酸-聚胞苷酸[poly（I:C）]刺激后，CgRel2 的表达显著上调。CgRel2 转染入人细胞系后，NF-κB、TNFα 和牡蛎白细胞介素 17（CgIL-17）报告基因的转录活性呈剂量依赖性激活，而 CgRel2 过表达不能诱导 ISRE（干扰素刺激反应元件）报告基因的转录活性。此外，免疫共沉淀结果表明，CgRel2 或 CgRel1 可与牡蛎 IκB1、IκB2 和 IκB3 蛋白强烈相互作用，这对于免疫信号转导和免疫功能的调节可能至关重要。综上所述，这些结果表明 CgRel2 可能对病原感染做出反应，参与免疫信号转导，激活 NF-κB、TNFα 和 CgIL-17 报告基因。因此，CgRel2 可能在牡蛎免疫系统中发挥重要作用。
