Thulasitha William Shanthakumar, Umasuthan Navaneethaiyer, Whang Ilson, Lim Bong-Soo, Jung Hyung-Bok, Noh Jae Koo, Lee Jehee
Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea.
Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea.
Fish Shellfish Immunol. 2015 Aug;45(2):560-6. doi: 10.1016/j.fsi.2015.05.002. Epub 2015 May 13.
Chemokines are small, structurally related chemotactic cytokines characterized by the presence of conserved cysteine residues. In the present study, we identified the cDNA of a CXC chemokine from Oplegnathus fasciatus, designated as OfCXCL12. An open reading frame of 297 bp encoded a 98 amino acid peptide with a putative signal peptide of 23 amino acids. The CXC family-specific small cytokine domain (SCY), which is highly conserved among vertebrates, was located between residues 29 and 87. The characteristic conserved cysteine residues in the CXC motif of OfCXCL12 were separated by tyrosine (Y). Similar to other vertebrate CXCL12 proteins, OfCXCL12 also lacked the ELR motif and hence belongs to ELR(-) subfamily. Phylogenetic analysis revealed two distinct clades, consisting of fish and tetrapod CXCL12 homologs. Constitutive expression with significantly higher levels of OfCXCL12 mRNA transcription was detected in immune-related organs, including the head kidney, spleen, and kidney. Infection with bacterial and viral agents led to significant upregulation of mRNA expression in both the head kidney and spleen, in a stimulant-specific manner. Stimulation of peripheral blood leukocytes by the mitogen concanavalin-A significantly induced OfCXCL12 transcription. Results from the present study suggest an important role for OfCXCL12 in immune defense against bacterial and viral infection in rock bream.
趋化因子是一类结构相关的小趋化性细胞因子，其特征是存在保守的半胱氨酸残基。在本研究中，我们从条石鲷中鉴定出一种CXC趋化因子的cDNA，命名为OfCXCL12。一个297 bp的开放阅读框编码一个98个氨基酸的肽，带有一个23个氨基酸的假定信号肽。在脊椎动物中高度保守的CXC家族特异性小细胞因子结构域（SCY）位于第29至87位残基之间。OfCXCL12的CXC基序中特征性的保守半胱氨酸残基被酪氨酸（Y）隔开。与其他脊椎动物的CXCL12蛋白相似，OfCXCL12也缺乏ELR基序，因此属于ELR（-）亚家族。系统发育分析揭示了两个不同的进化枝，分别由鱼类和四足动物的CXCL12同源物组成。在包括头肾、脾脏和肾脏在内的免疫相关器官中检测到OfCXCL12 mRNA转录水平显著更高的组成性表达。细菌和病毒病原体感染导致头肾和脾脏中的mRNA表达以刺激物特异性方式显著上调。促有丝分裂原伴刀豆球蛋白-A刺激外周血白细胞显著诱导OfCXCL12转录。本研究结果表明OfCXCL12在条石鲷抵抗细菌和病毒感染的免疫防御中起重要作用。
