Identification and functional characterization of IRAK-4 in grass carp (Ctenopharyngodon idellus)
Identification and functional characterization of IRAK-4 in grass carp (Ctenopharyngodon idellus)
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草鱼 (Ctenopharyngodon idellus) 中 IRAK-4 的鉴定和功能表征
DOI：
10.1016/j.fsi.2019.01.031
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发表时间：
2019
影响因子：
4.7
通讯作者：
Hu Chengyu
中科院分区：
文献类型：
--
作者：
Wu Chuxin;Xu Xiaowen;Zhi Xiaoping;Jiang Zeyin;Li Yinping;Xie Xiaofen;Chen Xingxing;Hu Chengyu
IL-1 R-associated kinase 4（IRAK 4）是先天免疫中的一种重要的TIR信号介导因子，可启动一系列信号转导，最终诱导炎症靶基因的表达。在本研究中，我们从草鱼（Ctenopharyngodon idella）中克隆并鉴定了IRAK 4的直向同源物。CiIRAK 4基因cDNA全长2057 bp，开放阅读框1422 bp，编码472个氨基酸。多重序列比对结果表明，IRAK 4在不同物种间高度保守。系统进化树分析表明，CiIRAK 4与斑马鱼IRAK 4具有较高的同源性。表达分析表明CiIRAK 4在所有受试组织中广泛表达。Poly I：C处理后，其表达明显上调，尤以肝、脾最为明显。Poly I：C和LPS均可诱导CIK细胞产生CiIRAK 4。荧光显微镜检测表明CiIRAK 4定位于细胞质中。RNAi介导的敲低和过表达分析表明，CiIRAK 4可能对NF-κ B p65从细胞质到细胞核的易位几乎没有影响，表明CiIRAK 4对于NF-κ B p65的激活是不敏感的。此外，IRAK 4促进IRF 5核转位，这与IRAK 4和IRF 5之间的相互作用无关。提示鱼类IRAK 4激酶通过间接途径调节IRF 5活性。
IL-1R-associated kinase 4 (IRAK4), a central TIR signaling mediator in innate immunity, can initiate a cascade of signaling events and lead to induction of inflammatory target gene expression eventually. In the present study, we cloned and characterized an IRAK4 orthologue from grass carp (Ctenopharyngodon idella). The full length cDNA ofCiIRAK4was 2057 bp with an ORF of 1422 bp encoding a polypeptide of 472 amino acids. Multiple alignments showed that IRAK4s were highly conserved among different species. Phylogenetic tree analysis revealed thatCiIRAK4 shared high homologous with zebra fish IRAK4. Expression analysis indicated thatCiIRAK4was widely expressed in all tested tissues. It was significantly up-regulated after treatment with poly I:C, especially obvious in liver and spleen. Also,CiIRAK4could be induced by poly I:C and LPS in CIK cells. Fluorescence microscopy assays showed thatCiIRAK4 localized in the cytoplasm. RNAi-mediated knockdown and overexpression assays indicated thatCiIRAK4 might have little effect on NF-kappa B p65 translocation from cytoplasm to nucleus, indicating thatCiIRAK4 was dispensable for activation of NF-kappa B p65. In addition, IRAK4 promoted IRF5 nuclear translocation, which has nothing to do with the interaction between IRAK4 and IRF5. It suggested that fish IRAK4 kinase regulated IRF5 activity through indirect ways.