Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China.
Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China.
Fish Shellfish Immunol. 2022 Nov;130:114-131. doi: 10.1016/j.fsi.2022.09.002. Epub 2022 Sep 7.
Chemokines are a group of secreted small molecules which are essential for cell migration in physiological and pathological conditions by binding to specific chemokine receptors. They are structurally classified into five groups, namely CXC, CC, CX3C, XC and CX. CC chemokine group is the largest one among them. In this study, we identified and characterized 61 CC chemokines from allotetraploid common carp (Cyprinus carpio). The sequence analyses showed that the majority of CC chemokines had an N-terminal signal peptide, and an SCY domain, and all CC chemokines were located in the extracellular region. Phylogenetic, evolutionary and syntenic analyses confirmed that CC chemokines were annotated as 11 different types (CCL19, CCL20, CCL25, CCL27, CCL32, CCL33, CCL34, CCL35, CCL36, CCL39, and CCL44), which exhibited unique gene arrangement pattern and chromosomal location respectively. Furthermore, genome synteny analyses between common carp and four representative teleost species indicated expansion of common carp CC chemokines resulted from the whole genome duplication (WGD) event. Additionally, the continuous evolution of gene CCL25s in teleost afforded a novel viewpoint to explain the WGD event in teleost. Then, we predicted the three-dimensional structures and probable function regions of common carp CC chemokines. All the CC chemokines core structures were constituted of an N-loop, a three-stranded β-sheet, and a C-terminal helix. Finally, 43 CC chemokines were predicted to have probable general antimicrobial activity. Their tertiary structures, cationic and amphiphilic physicochemical property supported the viewpoint. To verify the prediction, six recombinant CCL19s proteins were prepared and the antibacterial activity against Escherichia coli and Aeromonas hydrophila were verified. The results supported our prediction that rCCL19a.1s (rCCL19a.1_a, rCCL19a.1_b) and rCCL19bs (rCCL19b_a, rCCL19b_b), especially rCCL19bs, exhibited extremely significant inhibition to the growth of both E. coli and A. hydrophila. On the contrary, two rCCL19a.2s had no significant inhibitory effect. These studies suggested that CC chemokines were essential in immune system evolution and not monofunctional during pathogen infection.
趋化因子是一组分泌的小分子，通过与特定的趋化因子受体结合，在生理和病理条件下对于细胞迁移是必不可少的。它们在结构上被分为五个组，即 CXC、CC、CX3C、XC 和 CX。CC 趋化因子组是其中最大的一组。在这项研究中，我们从四倍体鲤鱼（Cyprinus carpio）中鉴定和表征了 61 种 CC 趋化因子。序列分析表明，大多数 CC 趋化因子具有 N 端信号肽和 SCY 结构域，并且所有 CC 趋化因子都位于细胞外区。系统发育、进化和基因共线性分析证实，CC 趋化因子被注释为 11 种不同类型（CCL19、CCL20、CCL25、CCL27、CCL32、CCL33、CCL34、CCL35、CCL36、CCL39 和 CCL44），它们分别表现出独特的基因排列模式和染色体位置。此外，鲤鱼和四种代表性硬骨鱼物种之间的基因组共线性分析表明，鲤鱼 CC 趋化因子的扩张是由全基因组复制（WGD）事件引起的。此外，硬骨鱼基因 CCL25 的连续进化为硬骨鱼的 WGD 事件提供了一个新的解释角度。然后，我们预测了鲤鱼 CC 趋化因子的三维结构和可能的功能区域。所有 CC 趋化因子的核心结构由 N 环、三股β-折叠和 C 端螺旋组成。最后，预测了 43 种 CC 趋化因子具有可能的一般抗菌活性。它们的三级结构、阳离子和两亲性理化性质支持了这一观点。为了验证这一预测，我们制备了六个重组 CCL19 蛋白并验证了它们对大肠杆菌和嗜水气单胞菌的抗菌活性。结果支持了我们的预测，即 rCCL19a.1s（rCCL19a.1_a、rCCL19a.1_b）和 rCCL19bs（rCCL19b_a、rCCL19b_b），尤其是 rCCL19bs，对大肠杆菌和嗜水气单胞菌的生长具有极其显著的抑制作用。相反，两个 rCCL19a.2s 没有显著的抑制作用。这些研究表明，CC 趋化因子在免疫系统进化中是必不可少的，而在病原体感染过程中并非是单一功能的。
