title: Molecular characterization of a fish-specific toll-like receptor 22 (TLR22) gene from common carp (Cyprinus carpio L.): Evolutionary relationship and induced expression upon immune stimulants.
abstract: In the host innate immune system, various pattern recognition receptors (PRRs) recognize conserved pathogens-associated molecular patterns (PAMPs), and represent an efficient first line of defense against invading pathogens. TLR22 is one of the fish-specific Toll-like receptors (TLRs), identified in a variety of fish species. In this study, we report the cloning and identification of a TLR22 cDNA from the gills of common carp (Cyprinus carpio L.). The full-length CcTLR22 cDNA was 3301 bp long, including a 32 bp 5'-untranslated region (UTR), an open reading frame (ORF) of 2838 bp and a 432 bp 3'-UTR.The CcTLR22 protein was found to comprise a signal peptide, 16 LRR domains, a LRRCT domain in the extracellular region and a TIR domain in the cytoplasmic region, which fits with the characteristic TLR domain architecture. The genomic organization of CcTLR22 was identified, which was encoded by an uninterrupted exon. Sequence alignment and phylogenetic analysis showed that all known teleost TLR22 members were clustered into an independent clade of the TLR22 family, and showed high amino acid identities with other fish TLRs. Real-time PCR assay showed that CcTLR22 mRNA was expressed in almost all tissues examined, while the levels obviously varied among different tissues. When challenged with poly(I:C) (a viral model) or A. hydrophila bacteria, the expression level of CcTLR22 was up-regulated in a variety of common carp tissues. These results indicate that CcTLR22 plays a significant role in systemic as well as mucosal defence after viral or bacterial stimulation or infection.
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China.
authors.forename: Guiwen
authors.initials: G
authors.lastname: Yang
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China.
authors.forename: Huiting
authors.initials: H
authors.lastname: Yang
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 9101, Wageningen 6700 HB, The Netherlands.
authors.forename: Jan H W M
authors.initials: JH
authors.lastname: Rombout
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan 250014, PR China. Electronic address: an.liguo58@gmail.com.
authors.forename: Liguo
authors.initials: L
authors.lastname: An
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D016980:Aeromonas hydrophila / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D002347:Carps / Q000145:classification / Q000235:genetics / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D007113:Immunity, Innate / Q000187:drug effects / Q000235:genetics; D009928:Organ Specificity; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D051193:Toll-Like Receptors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D051193:Toll-Like Receptors; D011070:Poly I-C
keywords: A. hydrophila; Common carp (Cyprinus carpio L.); Evolutionary relationship; Innate immunity; Poly(I:C); TLR22