title: Identification and characterization of three TLR1 subfamily members from the orange-spotted grouper, Epinephelus coioides.
abstract: Toll-like receptors (TLRs), which play important roles in host defense against pathogen infection, are the most intensively studied pattern recognition receptors (PRRs). In this study, we identified three novel TLR1 subfamily members, including TLR1 (EcTLR1b), TLR2 (EcTLR2b) and TLR14 (EcTLR14), from the orange-spotted grouper (Epinephelus coioides). EcTLR1b and EcTLR2b displayed low sequence identity with the previously reported grouper TLR1 (EcTLR1a) and TLR2 (EcTLR2a), respectively. The open reading frames (ORFs) of EcTLR1b, EcTLR2b and EcTLR14 contain 2484 bp, 2394 bp and 2640 bp, which encode the corresponding 827 amino acids (aa), 797 aa and 879 aa, respectively. All three TLRs have leucine-rich repeat (LRR) domains (including an LRR-NT (except for EcTLR1b), several LRR motifs and an LRR-CT), a trans-membrane region and a Toll/interleukin-1 receptor (TIR) domain. The TIR domains of the three TLRs exhibited conserved boxes, namely box1, box2 and box3, and their 3D models were similar to those of human TLR1 or TLR2. Sequence alignment demonstrated that the TIR domains of the three TLRs shared higher sequence identity with those of other species than the full-length receptors. Phylogenetic analysis indicated that EcTLR1s and EcTLR2s are characterized by their differing evolutionary status, whereas EcTLR14 was found to be in the same group as other piscine TLR14/18s. The three TLRs were ubiquitously expressed in seven tested tissues of healthy groupers, although their expression profiles were different. Post Cryptocaryon irritans infection, TLR1s expression was up-regulated in the gills. The expression of TLR2b was mainly increased in the spleen, but decreased in the gills, which was similar to the expression pattern of TLR2a post C. irritans infection. Unlike EcTLR1b and EcTLR2b, however, the grouper TLR14 transcript was substantially induced in both tissues post challenge. These findings may be helpful in understanding the innate immune mechanism of host anti-parasite infection.
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China; State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Yan-Wei
authors.initials: YW
authors.lastname: Li
authors.affiliation: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, Guangdong Province, PR China.
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
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: School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, Guangdong Province, PR China.
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China. Electronic address: lianxing@mail.sysu.edu.cn.
authors.forename: An-Xing
authors.initials: AX
authors.lastname: Li
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: D000818:Animals; D005075:Biological Evolution; D002478:Cells, Cultured; D016770:Ciliophora Infections / Q000276:immunology*; D003001:Cloning, Molecular; D005393:Fish Diseases / Q000276:immunology*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005880:Gills / Q000276:immunology* / Q000469:parasitology; D006801:Humans; D007113:Immunity, Innate; D010473:Perciformes / Q000276:immunology*; D010802:Phylogeny; D013154:Spleen / Q000276:immunology* / Q000469:parasitology; D051194:Toll-Like Receptor 1 / Q000235:genetics / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000235:genetics
chemical_list: D029941:Fish Proteins; C495342:TLR2 protein, human; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2
keywords: Cryptocaryon irritans; Epinephelus coioides; Innate immune; Toll-like receptor