Molecular characterization and evolutionary analysis of IL-17REL in Larimichthys crocea
- 海洋环境－已发表论文 
白细胞介素17受体(Interleukin 17 receptor,IL-17R)家族与IL-17细胞因子家族介导的各类反应有着密切联系.IL-17RE-like(IL-17REL)是一类最新发现的IL-17受体,其结构与IL-17RE相似,但尚未发现其配体.本研究克隆得到大黄鱼(Larimichthys crocea)IL-17REL(Lyc IL-17REL)的全长c DNA,其开放阅读框全长1 659个核苷酸,推断可编码一个由552个氨基酸组成的蛋白,含有信号肽、胞外段、跨膜区和胞内段.与其他物种的IL-17REL相似,Lyc IL-17REL蛋白的胞外段具有一个保守的FN I-like结构域,而胞内段缺少IL-17受体家族保守的SEFIR(SEF and IL-17R)结构域.多序列比对分析表明Lyc IL-17REL与日本河豚(Takifugu rubripes)IL-17REL的氨基酸序列同源性最高,序列一致性可达57.0%.系统进化分析表明,脊椎动物的IL-17受体家族可分为2类,IL-17RA/RB/RD为一类,IL-17RC/RE/REL为一类.其中鱼类及高等脊椎动物的IL-17REL与IL-17RE亲缘关系最近,并且推测二者可能是由同一基因从硬骨鱼类之前的物种中分化而来.组织分布表明Lyc IL-17REL在所有被检测的组织中为组成型表达,在黏膜相关组织如小肠和鳃中的表达量最高.大黄鱼受嗜水气单胞菌(Aeromonas hydrophila)诱导刺激后,Lyc IL-17REL在其头肾及鳃中的基因转录水平均显著上调.这表明Lyc IL-17REL可能在细菌感染引起的免疫反应中起着重要作用.Interleukin 17 receptor( IL-17R) family play important roles in IL-17 cytokine family mediated immune responses. IL-17RE-like is a novel IL-17 receptor whose ligand has not been found yet to date. In this paper,we cloned an IL-17 REL homologue from large yellow croaker and named it as Lyc IL-17 REL. The deduced open reading frame( ORF) of Lyc IL-17 REL is 1 659 nucleotides( nt),encoding a protein of 552 amino acids( aa) which consists of a signal peptide,an extracellular domain,a transmembrane region and an intracellular domain. The extracellular domain of Lyc IL-17 REL possesses a FN I-like domain,while intracellular domain loses the SEFIR domain which is conserved in IL-17 R family. Amino acid homology comparison shows that Lyc IL-17 REL has 57. 0% identity to Fugu( Takifugu rubripes) IL-17 REL. Based on the structural and phylogenetic analysis,the vertebrate IL-17 R family members were suggested to be classified into two groups: the IL-17 RA / RB / RD group and the IL-17 RC / RE / REL group. Besides this,we speculated that vertebrate IL-17 REL and IL-17 RE were probably differentiated the same ancestor from species older than teleosts. Lyc IL-17 REL was constitutively expressed in all tissues tested,especially in mucosal related tissues such as intestine and gills. The up-regulated expression of Lyc IL-17 REL was observed in head kidney and gills of large yellow croaker stimulated by Aeromonas hydrophila. These results suggested that Lyc IL-17 REL may play an important role in the immune response against bacterial infection.