State Key Laboratory of Freshwater Ecology and Biotechnology, And Key Laboratory of Aquaculture Disease Control, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China; The Innovation Academy of Seed Design, Chinese Academy of Sciences, Wuhan, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, And Key Laboratory of Aquaculture Disease Control, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province, 430072, China; The Innovation Academy of Seed Design, Chinese Academy of Sciences, Wuhan, China.
Dev Comp Immunol. 2021 Sep;122:104110. doi: 10.1016/j.dci.2021.104110. Epub 2021 Apr 29.
Toll/interleukin-1 receptor (TIR) domain-containing adaptors, serve as pivotal signal transduction molecules in Toll-like receptor (TLR) signalling pathway to mediate downstream signalling cascades. In this study, four TIR-domain containing adaptors, MyD88, TRIF, MAL and SARM, were identified in mandarin fish Siniperca chuatsi, and they all contain TIR domains, of which MyD88 and SARM had high sequence homology with their vertebrate homologues. The expression analysis at mRNA level indicated that these genes were ubiquitously distributed in different tissues, being high in immune- and mucosa-related tissues such as head-kidney and intestine. The transcripts of these adaptor genes were up-regulated by poly(I:C) and LPS stimulation in isolated head-kidney lymphocytes (HKLs) of mandarin fish. Fluorescence microscopy revealed that all these molecules were localized in cytoplasm, and further investigations showed that the over-expression of MyD88, TRIF and MAL activated the NF-κB, ISRE or type Ι IFN promoters and inhibited SVCV replication, whereas their antiviral effects were significantly impaired when co-transfected with SARM. It was also confirmed by co-immunoprecipitation (Co-IP) that SARM interacts separately with MyD88, TRIF and MAL, and MAL interacts with MyD88. However, the regulatory mechanisms of these adaptors involved in signalling pathways of different TLRs should be of interest for further research.
Toll/白细胞介素-1 受体（TIR）结构域包含的衔接蛋白，作为 Toll 样受体（TLR）信号通路中的关键信号转导分子，介导下游信号级联反应。在这项研究中，我们在鳜鱼（Siniperca chuatsi）中鉴定出四个 TIR 结构域包含的衔接蛋白，包括 MyD88、TRIF、MAL 和 SARM，它们都包含 TIR 结构域，其中 MyD88 和 SARM 与脊椎动物同源物具有很高的序列同源性。在 mRNA 水平的表达分析表明，这些基因在不同组织中广泛分布，在免疫和黏膜相关组织（如头肾和肠）中表达水平较高。在鳜鱼头肾淋巴细胞（HKLs）中，poly（I:C）和 LPS 刺激可诱导这些衔接子基因的转录物上调。荧光显微镜显示，这些分子均定位于细胞质中，进一步的研究表明，MyD88、TRIF 和 MAL 的过表达可激活 NF-κB、ISRE 或 I 型 IFN 启动子，并抑制 SVCV 复制，而当与 SARM 共转染时，它们的抗病毒作用则显著受损。共免疫沉淀（Co-IP）也证实了 SARM 分别与 MyD88、TRIF 和 MAL 相互作用，而 MAL 与 MyD88 相互作用。然而，这些衔接子在不同 TLR 信号通路中的作用机制仍有待进一步研究。
