Institute of Hydrobiology, Jinan University, Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering Ministry of Education, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, West 601 Huangpu Avenue, Tianhe District, Guangzhou, 510632, People's Republic of China.
College of Animal Science, Southwest University Rongchang Campus, 160 Xueyuan Road, Rongchang District, Chongqing, 402460, People's Republic of China.
Fish Shellfish Immunol. 2019 Mar;86:449-458. doi: 10.1016/j.fsi.2018.11.069. Epub 2018 Nov 30.
The complement system plays an important role in host defense against invading microorganisms. Complement component C9 is the last component that is involved in the formation of the membrane attack complex (MAC) on the surface of target cells. In the present study, the full length C9 cDNA sequence of 1984 bp with an open reading frame (ORF) of 1809 bp was cloned from southern catfish (Silurus meridionalis). The deduced amino acid sequence showed similarity with other teleost fish. The mRNA expression of C9 was detected in the liver, spleen, stomach, intestine, and head kidney, with highest levels detected in the liver. The mRNA of C9 was first detected in the yolk syncytial layer at 34 h post fertilization (hpf) with whole mount in situ hybridization, followed by the liver at 36 h post hatching (hph). The mRNA expression of C9 was upregulated significantly in the liver, spleen, and intestine following the injection with Aeromonas hydrophila, suggesting that C9 played an important role in defense against invading pathogens in southern catfish. Therefore, these results provide important information to understand the functions of C9 during fish early development in fish.
补体系统在宿主防御入侵微生物中发挥着重要作用。补体成分 C9 是最后一个参与靶细胞表面膜攻击复合物（MAC）形成的成分。在本研究中，从南方鲶鱼（Silurus meridionalis）中克隆出全长 1984bp 的 C9 cDNA 序列，其开放阅读框（ORF）为 1809bp。推导的氨基酸序列与其他硬骨鱼具有相似性。通过实时荧光定量 PCR 检测到 C9 在肝、脾、胃、肠和头肾中均有表达，其中肝中表达量最高。原位杂交结果显示，C9 的 mRNA 最早在受精后 34 小时（hpf）的卵黄合胞层中被检测到，孵化后 36 小时（hph）在肝中被检测到。Aeromonas hydrophila 注射后，C9 在肝、脾和肠中的 mRNA 表达水平显著上调，提示 C9 在南方鲶鱼抵抗入侵病原体的防御中发挥重要作用。因此，这些结果为了解鱼类早期发育过程中 C9 的功能提供了重要信息。
