title: Molecular characterization and biological effects of a CXCL8 homologue in large yellow croaker (Larimichthys crocea).
abstract: CXCL8 also called interleukin-8, is a CXC-type chemokine that plays a key role in promoting inflammation. Three subgroups of CXCL8 homologues have been reported in teleost fish, including CXCL8_L1, CXCL8_L2 and CXCL8_L3. In the present study, we identified a CXCL8 homologue belonging to CXCL8_L1 subgroup (LycCXCL8_L1) in large yellow croaker (Larimichthys crocea) that shares low identity to the previously reported large yellow croaker CXCL8 (LycCXCL8). The full-length cDNA of LycCXCL8_L1 is 716 nucleotides (nt) long and encodes a protein consisting of 99 amino acids (aa) with a putative molecular weight of 11.2 kDa. The deduced LycCXCL8_L1 protein contains a 22-aa signal peptide and a 77-aa mature polypeptide, which possesses an arrangement of four cysteines typical of other known CXC chemokines (C(34), C(36), C(60), and C(77)). Genomic analysis revealed that the LycCXCL8_L1 gene consisted of four exons and three introns and exhibited a similar exon-intron organization to LycCXCL8 and other species CXCL8 genes except for a different intron length. Phylogenetic analysis showed that both LycCXCL8_L1 and LycCXCL8 belong to CXCL8_L1 subgroup. LycCXCL8_L1 mRNA was constitutively expressed in all tissues examined although at different levels. Upon bacterial vaccine induction, LycCXCL8_L1 mRNA expression was rapidly increased in the spleen and head kidney tissues. Recombinant LycCXCL8_L1 and LycCXCL8 proteins produced in Escherichia coli both induced chemotaxis and superoxide production in peripheral blood leucocytes from large yellow croaker. These results indicate that two CXCL8_L1 molecules exist in large yellow croaker and play roles in inflammatory response.
authors.affiliation: Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China; Collaborative Innovation Center of Deep Sea Biology, Third Institute of Oceanography, State Oceanic Administration, Daxue Road 178, Xiamen 361005, PR China.
authors.forename: Yinnan
authors.initials: Y
authors.lastname: Mu
authors.affiliation: Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China; Collaborative Innovation Center of Deep Sea Biology, Third Institute of Oceanography, State Oceanic Administration, Daxue Road 178, Xiamen 361005, PR China.
authors.forename: Kunru
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China; Collaborative Innovation Center of Deep Sea Biology, Third Institute of Oceanography, State Oceanic Administration, Daxue Road 178, Xiamen 361005, PR China. Electronic address: ajingqun@tio.org.cn.
authors.forename: Jingqun
authors.initials: J
authors.lastname: Ao
authors.affiliation: Key Laboratory of Marine Biogenetics and Resources, Third Institute of Oceanography, State Oceanic Administration, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005, PR China; Collaborative Innovation Center of Deep Sea Biology, Third Institute of Oceanography, State Oceanic Administration, Daxue Road 178, Xiamen 361005, PR China. Electronic address: chenxinhua@tio.org.cn.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology; D001483:Base Sequence; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004926:Escherichia coli; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology*; D040461:Gene Components; D060226:Head Kidney / Q000378:metabolism; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000662:veterinary*; D016209:Interleukin-8 / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics*; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013154:Spleen / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D001428:Bacterial Vaccines; D018076:DNA, Complementary; D016209:Interleukin-8; D013481:Superoxides
keywords: CXCL8 (Interleukin-8); Chemotaxis; Gene expression pattern; Inflammatory response; Large yellow croaker (Larimichthys crocea)