title: Characterization and expression analysis of two novel CCR6 chemokine receptors and their three potential ligands CCL20Ls of grouper (Epinephelus coioides) post Cryptocaryon irritans infection.
abstract: CCR6 have been demonstrated playing an important role in immune cells homing to mucosal tissues, mediating antigen presentation and immune response in mammals. CCR6 in lower vertebrate leukocyte homing has not yet been revealed. Cryptocaryon irritans is believed to be a good pathogen model for skin and gill mucosal immunity. In this study, we identified two CCR6s and their three possible ligands CCL20 like cDNA sequences, designated as grouper EcCCR6A, EcCCR6B, EcCCL20L1, EcCCL20L2 and EcCCL20L3. It is interesting to find that EcCCR6A has a longer second extracellular loop than EcCCR6B, which is more similar to mammalian CCR6. Tissue distribution analysis showed that EcCCR6A pronouncedly dominates in gill and brain while EcCCR6B dominates in head kidney, trunk kidney and thymus. Three chemokine ligands have their own distinct expression pattern in health grouper tissues. EcCCL20L1 dominates in spleen and head kidney, EcCCL20L2 dominates in gill and thymus, whereas EcCCL20L3 dominates in skin and brain. The expression patterns of these chemokines and chemokine receptors were detected in C. irritans infected grouper and the results showed that EcCCR6A, EcCCR6B and EcCCL20L1 were significantly up-regulated in the skin of C. irritans infected fish, which indicated these two chemokine receptors and their ligand may play important role in immune cells' homing to skin mucosal immune tissues under pathogen caused inflammation.
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Ze-Quan
authors.initials: ZQ
authors.lastname: Mo
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Rui-Ai
authors.initials: RA
authors.lastname: Chen
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Yan-Wei
authors.initials: YW
authors.lastname: Li
authors.affiliation: State Key Laboratory of Biocontrol/Key Laboratory of Aquatic Product Safety (Sun Yat-Sen University), Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Xia-Zi
authors.initials: XZ
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Biocontrol/Key Laboratory of Aquatic Product Safety (Sun Yat-Sen University), Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: An-Xing
authors.initials: AX
authors.lastname: Li
authors.affiliation: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, PR China. Electronic address: xcluo@scut.edu.cn.
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Luo
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China. Electronic address: dxm72@scau.edu.cn.
authors.forename: Xue-Ming
authors.initials: XM
authors.lastname: Dan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001492:Bass; D054418:Chemokine CCL20 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016798:Ciliophora / Q000502:physiology; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018928:Immunity, Mucosal; D008024:Ligands; D009928:Organ Specificity; D010802:Phylogeny; D054399:Receptors, CCR6 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D054418:Chemokine CCL20; D029941:Fish Proteins; D008024:Ligands; D054399:Receptors, CCR6
keywords: CCL20; CCR6; Crytocaryon irritans; Epinephelus coioides