Jiangsu Key Laboratory of Biochemistry and Biotechnology of Marine Wetland, Yancheng Institute of Technology, Yancheng, Jiangsu Province, 224051, China.
College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu Province, 212003, China; Jiangsu Key Laboratory of Biochemistry and Biotechnology of Marine Wetland, Yancheng Institute of Technology, Yancheng, Jiangsu Province, 224051, China.
Fish Shellfish Immunol. 2018 Nov;82:200-211. doi: 10.1016/j.fsi.2018.08.033. Epub 2018 Aug 18.
Dabry's sturgeon (Acipenser dabryanus) is a useful model for the study of fish evolution, as it is one of the most primitive actinopterygian species. However, studies of the immune system of this fish are limited. Here, we identified three toll-like receptors (adaTLR21, adaTLR22, and adaTLR25) from Dabry's sturgeon. The three sturgeon TLRs had characteristic TLR features, including a signal peptide, several leucine rich repeat (LRR) domains, a transmembrane domain, and a Toll/interleukin-1 receptor (TIR) domain. Although the predicted amino acid sequences encoded by the sturgeon adaTLR21, adaTLR22, and adaTLR25 had somewhat low levels of sequence identity and similarity with TLRs from other fish species, the three sturgeon TLRs fell in well-supported clades with other teleost TLRs in our neighbor-joining phylogenetic tree. Real-time quantitative PCR showed that the three sturgeon TLRs were ubiquitously expressed in all examined tissues from healthy adult sturgeon, but that their expression patterns varied greatly among the different tissues. The three sturgeon TLRs were also expressed across all embryonic developmental stages that were examined, but their expression levels differed between developmental stages. All three TLRs were upregulated in head-kidney primary leucocytes following lipopolysaccharide (LPS) and polyinosinic: polycytidylic acid (polyI:C) stimulation. To the best of our knowledge, this is the first characterization of these three TLRs in Darby's sturgeon. Our results provide a framework for further studies of TLR ligand specificity and signaling pathways in sturgeon, and increase our understanding of the functional evolution of TLRs in vertebrates.
达氏鲟（Acipenser dabryanus）是研究鱼类进化的有用模式生物，因为它是最原始的硬骨鱼之一。然而，对这种鱼类免疫系统的研究是有限的。在这里，我们从达氏鲟中鉴定出了三种 Toll 样受体（adaTLR21、adaTLR22 和 adaTLR25）。这三种鲟鱼 TLR 具有典型的 TLR 特征，包括信号肽、几个富含亮氨酸的重复（LRR）结构域、跨膜结构域和 Toll/白细胞介素-1 受体（TIR）结构域。尽管由鲟鱼 adaTLR21、adaTLR22 和 adaTLR25 编码的预测氨基酸序列与来自其他鱼类的 TLR 具有较低的序列同一性和相似性，但这三种鲟鱼 TLR 与我们的邻接法系统发育树中的其他硬骨鱼 TLR 一起形成了支持良好的分支。实时定量 PCR 显示，这三种鲟鱼 TLR 在健康成年鲟鱼所有检测组织中均广泛表达，但在不同组织中的表达模式存在很大差异。这三种鲟鱼 TLR 也在所有检测到的胚胎发育阶段表达，但在不同发育阶段的表达水平不同。在头肾原代白细胞中，所有三种 TLR 均在脂多糖（LPS）和聚肌苷酸：聚胞苷酸（polyI:C）刺激后上调。据我们所知，这是首次对达氏鲟的这三种 TLR 进行表征。我们的研究结果为进一步研究鲟鱼 TLR 配体特异性和信号通路提供了框架，并增加了我们对 TLR 在脊椎动物中功能进化的理解。
