Identification and expression analysis of sixteen Toll-like receptor genes, TLR1, TLR2a, TLR2b, TLR3, TLR5M, TLR5S, TLR7−9, TLR13a−c, TLR14, TLR21−23 in mandarin fish Siniperca chuatsi

• Published in: Developmental and comparative immunology 2021-08, Vol.121, p.104100-104100, Article 104100
• Main Authors: Wang, Kai Lun, Chen, Shan Nan, Huo, Hui Jun, Nie, Pin
• Format: Article
• Language: English
• Subjects: Animals; Computational Biology; Domains; Fish; Fish Diseases - immunology; Fish Proteins - genetics; Fish Proteins - metabolism; Fishes - genetics; Fishes - immunology; Gene Expression Profiling; Genes; Head Kidney - cytology; Head Kidney - immunology; Head Kidney - metabolism; Immune response; Immune system; Immunity, Innate; Innate immune response; Interleukins; Intestine; Kidneys; Leucine; Lipopolysaccharides; Lipopolysaccharides - immunology; Lymphocytes; Lymphocytes - immunology; Lymphocytes - metabolism; Mandarin fish; Mucosa; Pattern recognition; Pattern recognition receptors; Phylogeny; Poly I-C - immunology; Polyinosinic:polycytidylic acid; Protein Domains - genetics; Proteins; Receptors; Sequence Analysis, DNA; Siniperca chuatsi; Spleen; Stimulation; Tissues; TLR1 protein; TLR3 protein; TLR5 protein; TLR7 protein; TLR9 protein; Toll-like receptors; Toll-Like Receptors - genetics; Toll-Like Receptors - metabolism; Up-Regulation - immunology
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2021.104100

Toll-like receptors (TLRs), as a family of pattern recognition receptors (PRRs), possess specific pathogen-related molecular pattern (PAMP) recognition spectrum in inducing immune responses. In this study, sixteen TLRs were identified and characterized in mandarin fish (Siniperca chuatsi). All these TLRs consist of leucine-rich repeats (LRRs), a transmembrane domain and a Toll/interleukin-I receptor (TIR) domain, with the exception of TLR5S which lacks TIR domain, and they can be clustered into five branches, i.e. TLR1 subfamily, TLR3 subfamily, TLR5 subfamily, TLR7 subfamily and TLR11 subfamily in phylogenetic tree. These TLR genes were expressed in all tested tissues and had high expression levels in immune-related tissues such as head-kidney and spleen or mucosa-related tissues such as intestine and pyloric caecum. The transcripts of TLR2a, TLR2b, TLR3, TLR13a, TLR14, TLR22 and TLR23 were all significantly up-regulated after stimulation with poly(I:C); TLR1, TLR2a, TLR2b, TLR3, TLR5M, TLR5S, TLR13a and TLR13b transcripts were all significantly up-regulated after stimulation with PGN; and TLR2a, TLR2b, TLR5M, TLR5S, TLR7, TLR8, TLR9, TLR13c, TLR14 and TLR22 transcripts were all significantly up-regulated after stimulation with LPS in isolated head kidney lymphocytes of mandarin fish. The findings in this study may provide a valuable basis for functional study on TLR genes in mandarin fish. •Sixteen TLR genes were bioinformatically characterized in mandarin fish S. chuatsi.•Conservation in domain composition was observed in homologues of these TLRs.•These sixteen TLR genes were constitutively expressed in examined tissues.•These TLR genes were highly expressed in immune and mucosa-related tissues.•The expression profiles of these genes were analyzed after poly(I:C), LPS and PGN stimulation in HKLs.