Toll-Like Receptor 5 of Golden Pompano Trachinotus ovatus (Linnaeus 1758): Characterization, Promoter Activity and Functional Analysis

• Published in: International journal of molecular sciences 2020-08, Vol.21 (16), p.5916
• Main Authors: Zhu, Ke-Cheng, Wu, Meng, Zhang, Dian-Chang, Guo, Hua-Yang, Zhang, Nan, Guo, Liang, Liu, Bao-Suo, Jiang, Shi-Gui
• Format: Article
• Language: English
• Subjects: Amino acid sequence; Amino acids; Animals; Bacteria; Bacterial infections; Binding sites; CCAAT-Enhancer-Binding Protein-alpha - genetics; CCAAT-Enhancer-Binding Protein-alpha - metabolism; CCAAT/enhancer-binding protein; Conserved sequence; Domains; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - metabolism; Fishes - genetics; Fishes - metabolism; Flagellin; Functional analysis; GATA1 Transcription Factor - genetics; GATA1 Transcription Factor - metabolism; Gene expression; Immune response; Immune system; Infections; Interferon; Intestinal Mucosa - metabolism; Intestine; Kidney - metabolism; Lipopolysaccharides; Liver; Liver - metabolism; Microorganisms; Molecular weight; Muscles; NF-kappa B - genetics; NF-kappa B - metabolism; NF-κB protein; Open reading frames; Pathogens; Pattern recognition; Peptidoglycans; Polyinosinic:polycytidylic acid; Polypeptides; Promoter Regions, Genetic; Protein Domains; Proteins; Signal Transduction; TLR5 protein; Toll-Like Receptor 5 - chemistry; Toll-Like Receptor 5 - genetics; Toll-Like Receptor 5 - metabolism; Toll-like receptors; Trachinotus ovatus; Transcription factors
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21165916

Toll-like receptors (TLRs), as important pattern recognition receptors, represent a significant component of fish immune systems and play an important role in resisting the invasion of pathogenic microorganisms. The TLR5 subfamily contains two types of TLR5, the membrane form of TLR5 (TLR5M) and the soluble form of TLR5 (TLR5S), whose detailed functions have not been completely elucidated. In the present study, we first identified two genes, ( ) and ( ), from golden pompano ( ). The full-length and cDNA are 3644 bp and 2329 bp, respectively, comprising an open reading frame (ORF) of 2673 bp, encoding 890 amino acids, and an ORF of 1935 bp, encoding 644 amino acids. Both the possess representative TLR domains; however, only has transmembrane and intracellular TIR domains. Moreover, the transcription of two was significantly upregulated after stimulation by polyinosinic:polycytidylic acid (poly (I:C)), lipopolysaccharide (LPS), and flagellin in both immune-related tissues (liver, intestine, blood, kidney, and skin) and nonimmune-related tissue (muscle). Furthermore, the results of bioinformatic and promoter analysis show that the transcription factors GATA-1 (GATA Binding Protein 1), C/EBPalpha (CCAAT Enhancer Binding Protein Alpha), and ICSBP (Interferon (IFN) consensus sequence binding protein) may play a positive role in moderating the expression of two . Overexpression of and notably increases (nuclear factor kappa-B) activity. Additionally, the binding assay revealed that two rToTLR5s can bind specifically to bacteria and pathogen-associated molecular patterns (PAMPs) containing , , , , , , , LPS, poly(I:C), flagellin, and peptidoglycan (PGN). In conclusion, the present study may help to elucidate the function of ToTLR5M/S and clarify their possible roles in the fish immune response to bacterial infection.