Cloning，expression and functional identification of CD209 gene in Nile tilapia Oreochromis niloticus
LUO Guoling1,2,3, WANG Xiaoqian1, JIAN Jichang1,2,3, LU Yishan1,2,3, TANG Jufen1,2,3, HUANG Yu1,2,3*
1.College of Fisheries， Guangdong Ocean University, Zhanjiang 524088, China; 2.Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524088, China; 3.Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institute, Zhanjiang 524088, China
Abstract: To further understand the molecular structure, expression characteristics and immune function of CD209 in Nile tilapia Oreochromisniloticus (OnCD209)with body mass of (100±5)g, bioinformatics software was used to analyze OnCD209 amino acid sequence of the open reading frame (ORF) in Nile tilapia, and the relative expression of OnCD209 in healthy tilapia tissues including liver, spleen, gill and intestine post Streptococcusagalactiae infection was detected by real-time fluorescent quantitative PCR (RT-qPCR), and CD209-pEGFP-N1 and CD209-pcDNA3.1 vectors were constructed to study the localization of OnCD209 molecular in 293T cells and its influence on NF-κB enzyme activity. The results showed that the ORF region of OnCD209 was found to be 1 383 bp, encoding 460 amino acids, and to have a carbohydrate recognition domain, accordance with the C-type lectin family. Multiple sequence alignment showed that OnCD209 was note conserved among species. Phylogenetic tree analysis revealed that OnCD209 were closely related to grassfish Liparistanakae. Tissue expression showed that OnCD209 was detected in all tissues (brain, blood, skin, muscle, head kidney, intestine, gill, liver, spleen and thymus) with the maximal expression level in blood. The up-regulated expression of OnCD209 was observed in all detected tissues of Nile tilapia exposed to S.agalactiae infection in 6 h, then down-regulated at 12 h and 24 h，and then up-regulated at 48 h (P<0.05). Subcellular localization analysis showed that OnCD209 was locatzed on the cytomembrane and the dual-luciferase reporter system indicated that OnCD209 significantly enhanced the NF-κB enzyme activity. The findings indicated that OnCD209 was involved in the immune response to bacteria and inflammatory response in Nile tilapia, which provides a theoretical basis for further study on the biological function of OnCD209.
2021, Vol. 36 
