title: Genomic characterization and expression analysis of five novel IL-17 genes in the Pacific oyster, Crassostrea gigas.
abstract: Interleukin-17 (IL-17) is a proinflammatory cytokine that plays an important role in clearing extracellular bacteria and contributes to the pathology of many autoimmune and allergic conditions. In the present study, five novel IL-17 homologs were identified by searching and analyzing the Pacific oyster genome. All six CgIL-17 members (including a previously reported homolog) contained four conserved cysteines that were used in the formation of disulfide bonds. Phylogenetic analysis showed that all invertebrate IL-17s were clustered into one group, implying that invertebrate IL-17s evolved from one common ancestral gene and subsequently diversified. All CgIL-17s shared the same genomic structure, containing two exons and one intron, except for the CgIL-17-3 and CgIL-17-5 genes, which each had only one exon. The expression pattern of the CgIL-17 genes was analyzed by qRT-PCR in a variety of tissues and at different developmental stages, and these genes were highly expressed in the gill and digestive gland tissues. Moreover, the expression of the CgIL-17 family genes was significantly up-regulated in hemocytes challenged with Pathogen-Associated Molecular Patterns (PAMPs). CgIL-17-3 had a strong response to lipopolysaccharide (LPS) and heat-killed Vibrio alginolyticus (HKVA) challenge, while CgIL-17-5 and CgIL-17-6 can be activated by peptidoglycan (PGN), but not by heat-killed Listeria monocytogenes (HKLM). The distinct, up-regulated transcript levels of the CgIL-17s in response to PAMPs challenge further indicate that CgIL-17s are likely to be significant components of immune responses by playing diversified roles in host defense in the Pacific oyster. These findings suggest that CgIL-17s are involved in innate immune responses and further supports their conserved function in mollusks immunity.
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Yuehuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Xiang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Fufa
authors.initials: F
authors.lastname: Qu
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. Electronic address: carlzyu@scsio.ac.cn.
authors.forename: Ziniu
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000276:immunology; D049896:Crassostrea / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000382:microbiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D016678:Genome; D020381:Interleukin-17 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000276:immunology / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D000276:Adjuvants, Immunologic; D020381:Interleukin-17; D011135:Polysaccharides, Bacterial; D011070:Poly I-C
keywords: Genomic organization; Interleukin-17; PAMPs challenge; Pacific oyster