Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China.
Fish Shellfish Immunol. 2010 Mar;28(3):445-52. doi: 10.1016/j.fsi.2009.11.024. Epub 2009 Dec 11.
A CXCL13-like chemokine cDNA was isolated from large yellow croaker (Pseudosciaena crocea) by expressed sequence tag (EST) analysis (LycCXCL13). The full-length cDNA of LycCXCL13 is 796 nucleotides (nt) encoding a protein of 97 amino acids (aa), with a putative molecular weight of 10.7 kDa. The deduced LycCXCL13 contains a 24-aa signal peptide and a 73-aa mature polypeptide, which possesses the typical arrangement of four cysteines as found in other known CXC chemokines (C(25), C(27), C(52) and C(68)). It shares 35, 36 and 39% aa sequence identities to green puffer CXCL13-like, Atlantic salmon CXCL13 and Japanese flounder CXCL13 chemokines, and 24-29% identities to CXCL13 chemokines in mammals, respectively. Phylogenetic analysis showed that LycCXCL13 is more closely related to the CXCL13 subgroup than to any other CXC chemokine subgroups. LycCXCL13 gene was constitutively expressed in all tissues examined, except for intestine. Upon induction with poly(I:C) or inactivated trivalent bacterial vaccine, LycCXCL13 gene expression was significantly up-regulated in spleen, head kidney, heart and gills at 24 h post-injection. Real-time PCR results showed that LycCXCL13 gene expression reached peak level in spleen and head kidney at 12 h after induction by poly(I:C), while its expression increased to the highest level in head kidney at 24 h or in spleen at 48 h by bacterial vaccine. Recombinant LycCXCL13 protein produced in E. coli BL21 exhibited obvious chemotaxis to the peripheral blood leucocytes (PBLs) from large yellow croaker. These results suggest that LycCXCL13 may be involved in inflammatory responses as well as homeostatic processes in large yellow croaker.
通过表达序列标签 (EST) 分析，从大黄鱼 (Pseudosciaena crocea) 中分离出 CXCL13 样趋化因子 cDNA (LycCXCL13)。LycCXCL13 的全长 cDNA 为 796 个核苷酸 (nt)，编码 97 个氨基酸 (aa) 的蛋白质，推测分子量为 10.7 kDa。推导的 LycCXCL13 包含 24 个氨基酸的信号肽和 73 个氨基酸的成熟多肽，具有其他已知 CXC 趋化因子中发现的典型四个半胱氨酸排列 (C(25)、C(27)、C(52)和 C(68))。它与绿鳍马面鲀 CXCL13 样、大西洋鲑 CXCL13 和日本牙鲆 CXCL13 趋化因子的 aa 序列分别具有 35%、36%和 39%的同源性，与哺乳动物的 CXCL13 趋化因子的 aa 序列分别具有 24%-29%的同源性。系统进化分析表明，LycCXCL13 与 CXCL13 亚组的关系比与任何其他 CXC 趋化因子亚组的关系更密切。LycCXCL13 基因在所有检测的组织中均呈组成性表达，除了肠道。在用 poly(I:C) 或失活的三价细菌疫苗诱导后，LycCXCL13 基因在注射后 24 小时在脾脏、头肾、心脏和鳃中显著上调。实时 PCR 结果显示，在 poly(I:C) 诱导后 12 小时，LycCXCL13 基因在脾脏和头肾中达到表达高峰，而在头肾中 24 小时或在脾脏中 48 小时细菌疫苗诱导后表达水平最高。在大肠杆菌 BL21 中表达的重组 LycCXCL13 蛋白对大黄鱼外周血白细胞 (PBL) 表现出明显的趋化作用。这些结果表明，LycCXCL13 可能参与大黄鱼的炎症反应和稳态过程。
