Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China; Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
Fish Shellfish Immunol. 2019 Apr;87:73-81. doi: 10.1016/j.fsi.2019.01.004. Epub 2019 Jan 4.
C1q-domain-containing (C1qDC) proteins, which are involved in a series of immune responses, are important pattern recognition receptors in innate immunity in vertebrates and invertebrates. Functional studies of C1qDC proteins in vertebrates are scarce. In the present study, a C1qDC protein (SsC1qDC) from the teleost black rockfish (Sebastes schlegelii) was identified and examined at expression and functional levels. The open reading frame of SsC1qDC is 636 bp, and the predicted amino acid sequence of SsC1qDC shares 62%-69% overall identity with the C1qDC proteins of several fish species. SsC1qDC possesses conserved C1qDC features, including a signal sequence and a C1q domain. SsC1qDC was expressed in different tissues and its expression was up-regulated by bacterial and viral infection. Recombinant SsC1qDC (rSsC1qDC) exhibited apparent binding activities against PAMPs including LPS and PGN. rSsC1qDC had antibacterial activity against Vibrio parahaemolyticus, and was able to enhance the phagocytic activity of macrophages towards Vibrio anguillarum. rSsC1qDC interacted with human heat-aggregated IgG. Furthermore, in the presence of rSsC1qDC, fish exhibited enhanced resistance against bacterial infection. Collectively, these results indicated that SsC1qDC serves as a pattern recognition receptor and plays a vital role in the defense system of black rockfish.
C1q 结构域包含蛋白（C1qDC 蛋白）参与了一系列免疫反应，是脊椎动物和无脊椎动物固有免疫中重要的模式识别受体。在脊椎动物中，C1qDC 蛋白的功能研究较少。本研究从硬骨鱼青石斑鱼（Sebastes schlegelii）中鉴定并研究了一种 C1qDC 蛋白（SsC1qDC），从表达和功能水平进行了研究。SsC1qDC 的开放阅读框为 636bp，其预测的氨基酸序列与几种鱼类的 C1qDC 蛋白具有 62%-69%的整体同一性。SsC1qDC 具有保守的 C1qDC 特征，包括信号序列和 C1q 结构域。SsC1qDC 在不同组织中表达，其表达在细菌和病毒感染时被上调。重组 SsC1qDC（rSsC1qDC）对 LPS 和 PGN 等 PAMP 具有明显的结合活性。rSsC1qDC 对副溶血弧菌具有抗菌活性，并能增强巨噬细胞对鳗弧菌的吞噬活性。rSsC1qDC 与人热聚集 IgG 相互作用。此外，在存在 rSsC1qDC 的情况下，鱼类对细菌感染的抵抗力增强。综上所述，这些结果表明 SsC1qDC 作为一种模式识别受体，在青石斑鱼的防御系统中发挥着重要作用。
