Molecular cloning and expression analysis of toll‐like receptor genes (TLR7, TLR8 and TLR9) of golden pompano (Trachinotus ovatus)
Molecular cloning and expression analysis of toll‐like receptor genes (TLR7, TLR8 and TLR9) of golden pompano (Trachinotus ovatus)
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DOI：
10.1016/j.fsi.2017.02.026
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发表时间：
2017-04
影响因子：
4.7
通讯作者：
Youchuan Wei;Shu Hu;Baobao Sun;Qihuan Zhang;G. Qiao;Zisheng Wang;Rong Shao;Guoqiang Huang;Z. Qi
中科院分区：
文献类型：
--
作者：
Youchuan Wei;Shu Hu;Baobao Sun;Qihuan Zhang;G. Qiao;Zisheng Wang;Rong Shao;Guoqiang Huang;Z. Qi
Toll样受体(Toll Like Receptor，TLR)7、8和9是细胞内的TLRs，在宿主对细菌或病毒病原体的免疫防御中发挥重要作用。本研究从经济价值较高的海洋硬骨鱼--金腹鱼(Trachinotus Ovatus)中鉴定出TLR7、8和9。序列分析表明，这3个TLRs包含一些保守的特征，包括信号肽、25个富含亮氨酸重复序列(LRR)基序、一个跨膜结构域和一个TIR基序。这三个TLR与其他硬骨鱼的TLR具有很高的序列同源性和相似性。系统进化树分析表明，这3个TLR与其对应的鱼类很好地聚在了一起，证实了它们命名的正确性和进化过程中的密切关系。实时荧光定量聚合酶链式反应显示，这三种TLRs在正常胎盘组织中普遍表达，其中在脾和头肾组织中表达较高，提示它们在免疫反应中起作用。此外，Pompano TLR7和TLR8在PolyI：C攻击后12h至48h在脾和头肾中表达上调，但对溶血性弧菌感染没有影响。Pompano TLR9可被溶藻弧菌感染诱导，但对PolyI：C攻击反应迟钝。这些结果表明，Pompano TLR7、8和9在应答细菌或病毒病原体方面可能具有不同的作用。我们的结果为进一步研究鱼类TLRs的配基特异性和信号转导途径奠定了基础，为阐明鱼类TLRs的免疫功能奠定了基础。
Toll like receptor (TLR) 7, 8 and 9 are intracellular TLRs which play important roles in host immune defense against bacterial or virus pathogens. In this study, TLR7, 8 and 9 were identified from golden pompano (Trachinotus ovatus), a marine teleost with great economic values. Sequence analysis revealed that the three TLRs contained several conserved characteristic features, including signal peptides, 25 leucine-rich repeat (LRR) motifs, a transmembrane domain and a TIR motif. These three TLRs shared high sequence identity and similarity with their counterparts from other teleosts. The phylogenetic tree analysis showed the three TLRs were clustered well with their piscine counterparts, confirming the correctness of their nomenclatures and closed relationships during evolution. Quantitative real-time PCR revealed that the three TLRs were ubiquitously expressed in all the tested tissues from normal pompano, with high expression in spleen and head kidney, indicating their role in immune reaction. Further, pompano TLR7 and TLR8 was up-regulated in spleen and head kidney from 12 h to 48 h following polyI:C challenge, but remained no changes to Vibrioalginilyticusinfection. In contrast, pompano TLR9 could be induced byV. alginilyticusinfection but remained apathetic to polyI:C challenge. These results indicated that pompano TLR7, 8 and 9 might have distinct roles in response to bacterial or virus pathogens. Our results provided the basis for further study on ligand specificity and signaling pathways of fish TLRs which are required for elucidating the immune functions of fish TLRs.