title: Molecular characterization and transcriptional analysis of non-mammalian type Toll like receptor (TLR21) from rock bream (Oplegnathus fasciatus).
abstract: Toll-like receptors (TLRs) are a large family of pattern recognition receptors, which are involved in triggering host immune responses against various pathogens by detecting their evolutionarily conserved pathogen associated molecular patterns (PAMPs). TLR21 is a non-mammalian type TLR, which recognizes unmethylated CpG DNA, and is considered as a functional homolog of mammalian TLR9. In this study, we attempted to identify and characterize a novel TLR21 counterpart from rock bream (Oplegnathus fasciatus) designated as RbTLR21, at molecular level. The complete coding sequence of RbTLR21 was 2919bp in length, which encodes a polypeptide of 973 amino acids with a predicted molecular mass of 112kDa and a theoretical isoelectric point of 8.6. The structure of the deduced RbTLR21 protein is similar to that of the members of typical TLR family, and includes the ectodomain, which consists of 16 leucine rich repeats (LRRs), a transmembrane domain, and a cytoplasmic Toll/interleukin-1 receptor (TIR) domain. According to the pairwise sequence analysis data, RbTLR21 was homologous to that of the orange-spotted grouper (Epinephelus coioides) with 76.9% amino acid identity. Furthermore, our phylogenetic analysis revealed that RbTLR21 is closely related to E. coioides TLR21. The RbTLR21 was ubiquitously expressed in all the tissues tested, but the highest expression was found in spleen. Additionally, upon stimulation with Streptococcus iniae, rock bream iridovirus (RBIV), and Edwardsiella tarda, RbTLR21 mRNA was significantly up-regulated in spleen tissues. Collectively, our findings suggest that RbTLR21 is indeed an ortholog of the TLR21 family and may be important in mounting host immune responses against pathogenic infections.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Thanthrige Thiunuwan
authors.initials: TT
authors.lastname: Priyathilaka
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Don Anushka Sandaruwan
authors.initials: DA
authors.lastname: Elvitigala
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Bong-Soo
authors.initials: BS
authors.lastname: Lim
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Hyung-Bok
authors.initials: HB
authors.lastname: Jeong
authors.affiliation: Department of Biotechnology, Division of Applied Chemistry & Biotechnology, Hanbat National University, Daejeon 305-719, Republic of Korea.
authors.forename: Sang-Yeob
authors.initials: SY
authors.lastname: Yeo
authors.affiliation: Division of Marine Environment and Bioscience, Korea Maritime University, Busan 606-791, Republic of Korea.
authors.forename: Cheol Young
authors.initials: CY
authors.lastname: Choi
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D018076:DNA, Complementary; D005399:Fishes / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D051193:Toll-Like Receptors / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D051193:Toll-Like Receptors
keywords: Oplegnathus fasciatus; Toll-like receptor 21 (TLR21); Transcriptional modulation