Fu Qiang, Yang Yujia, Li Chao, Zeng Qifan, Zhou Tao, Li Ning, Liu Yang, Li Yun, Wang Xiaozhu, Liu Shikai, Li Daoji, Liu Zhanjiang
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
Dev Comp Immunol. 2017 Aug;73:97-108. doi: 10.1016/j.dci.2017.03.012. Epub 2017 Mar 18.
Chemokines are a superfamily of structurally related chemotactic cytokines exerting significant roles in regulating cell migration and activation. Based on the arrangement of the first four cysteine residues, they are classified into CC, CXC, C and CX3C subfamilies. In this study, a complete set of 64 CC chemokine ligand (CCL) genes was systematically identified, annotated, and characterized from the channel catfish genome. Extensive phylogenetic and comparative genomic analyses supported their annotations, allowing establishment of their orthologies, revealing fish-specific CC chemokines and the expansion of CC chemokines in the teleost genomes through lineage-specific tandem duplications. With 64 genes, the channel catfish genome harbors the largest numbers of CC chemokines among all the genomes characterized to date, however, they fall into 11 distinct CC chemokine groups. Analysis of gene expression after bacterial infections indicated that the CC chemokines were regulated in a gene-specific and time-dependent manner. While only one member of CCL19 (CCL19a.1) was significantly up-regulated after Edwardsiella ictaluri infection, all CCL19 members (CCL19a.1, CCL19a.2 and CCL19b) were significantly induced after Flavobacterium columnare infection. In addition, CCL19a.1, CCL19a.2 and CCL19b were also drastically up-regulated in ESC-susceptible fish, but not in resistant fish, suggesting potential significant roles of CCL19 in catfish immune responses. High expression levels of certain CC appeared to be correlated with susceptibility to diseases and intolerance to hypoxia.
趋化因子是一类结构相关的趋化性细胞因子超家族，在调节细胞迁移和激活方面发挥着重要作用。根据前四个半胱氨酸残基的排列方式，它们被分为CC、CXC、C和CX3C亚家族。在本研究中，从斑点叉尾鮰基因组中系统地鉴定、注释并表征了一套完整的64个CC趋化因子配体（CCL）基因。广泛的系统发育和比较基因组分析支持了它们的注释，确定了它们的直系同源关系，揭示了鱼类特有的CC趋化因子以及硬骨鱼基因组中通过谱系特异性串联重复导致的CC趋化因子的扩增。斑点叉尾鮰基因组中有64个基因，是迄今为止所有已表征基因组中CC趋化因子数量最多的，然而，它们分为11个不同的CC趋化因子组。细菌感染后的基因表达分析表明，CC趋化因子以基因特异性和时间依赖性方式受到调控。在爱德华氏菌感染后，只有CCL19的一个成员（CCL19a.1）显著上调，而在柱状黄杆菌感染后，所有CCL19成员（CCL19a.1、CCL19a.2和CCL19b）均显著诱导表达。此外，CCL19a.1、CCL19a.2和CCL19b在易患ESC的鱼类中也大幅上调，但在抗性鱼类中则不然，这表明CCL19在斑点叉尾鮰免疫反应中可能具有重要作用。某些CC的高表达水平似乎与疾病易感性和低氧耐受性相关。
