Ou Mi, Huang Rong, Xiong Lv, Luo Lifei, Chen Geng, Liao Lanjie, Li Yongming, He Libo, Zhu Zuoyan, Wang Yaping
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Fish Shellfish Immunol. 2017 Apr;63:480-490. doi: 10.1016/j.fsi.2017.02.030. Epub 2017 Feb 20.
Grass carp (Ctenopharyngodon idellus) is an economical aquaculture species in China, and the Grass Carp Reovirus (GCRV) that causes hemorrhagic disease seriously affects the grass carp cultivation industry. Substantial evidence indicates that there is an association between the membrane-associated RING-CH family of E3 ligase (MARCH) family and immune defense in mammals, while functional studies on non-mammalian MARCH proteins are limited. In order to know the characteristics of the MARCH genes in C. idellus, eight MARCH genes (MARCH1, 2, 5, 6, 7, 8, 9 and 11) were cloned and the open reading frames (ORF) were identified in grass carp. All MARCH proteins in grass carp contained an RING-CH domain, which is characteristic of the MARCH protein. The phylogenetic analysis revealed that different MARCH proteins gathered into their separate clusters. All eight members of the MARCH gene family were detected in all tissues sampled, but the relative expression level differed. In addition, the mRNA expression of all the MARCHs was regulated at different levels in the immune organs after a GCRV challenge, and they responded robustly in both the intestine and liver. The mRNA expression of MARCH8, MHC II, TfR, IL1RAP, EGR1, and DUSP1 in the intestine after GCRV infection was analyzed, and the results showed that MARCH8 could negatively regulate TfR, IL1RAP, EGR1, and DUSP1, which signaled via the MAPK or NF-κB-activation pathways that play vital roles in immunity. Our findings identified a novel gene family in C. idellus and provided novel evidence that MARCH genes are inducible and involved in the immune response. Moreover, MARCH8 might function to negatively regulate immune receptors in C. idellus. Therefore, the MARCH might play a vital role in regulating the immune response of C. idellus.
草鱼（Ctenopharyngodon idellus）是中国一种经济的水产养殖品种，而引起出血性疾病的草鱼呼肠孤病毒（GCRV）严重影响草鱼养殖业。大量证据表明，E3泛素连接酶膜相关RING-CH结构域（MARCH）家族与哺乳动物的免疫防御之间存在关联，而非哺乳动物MARCH蛋白的功能研究有限。为了了解草鱼中MARCH基因的特征，克隆了8个MARCH基因（MARCH1、2、5、6、7、8、9和11），并在草鱼中鉴定出开放阅读框（ORF）。草鱼中的所有MARCH蛋白都含有一个RING-CH结构域，这是MARCH蛋白的特征。系统发育分析表明，不同的MARCH蛋白聚集在各自的簇中。在所有采样组织中均检测到MARCH基因家族的所有8个成员，但相对表达水平有所不同。此外，在GCRV攻击后，所有MARCHs的mRNA表达在免疫器官中受到不同程度的调节，并且它们在肠道和肝脏中均有强烈反应。分析了GCRV感染后肠道中MARCH8、MHC II、TfR、IL1RAP、EGR1和DUSP1的mRNA表达，结果表明MARCH8可以负调节TfR、IL1RAP、EGR1和DUSP1，这些蛋白通过在免疫中起重要作用的MAPK或NF-κB激活途径发出信号。我们的研究结果在草鱼中鉴定出一个新的基因家族，并提供了新的证据表明MARCH基因是可诱导的且参与免疫反应。此外，MARCH8可能在草鱼中负调节免疫受体。因此，MARCH可能在调节草鱼的免疫反应中起重要作用。
