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Molecular cloning of sea perch ( Lateolabrax japonicus ) TLR 1 and analysis of its expression pattern after stimulation with various bacteria
Author(s) -
Li Fuxiang,
Wang Pengfei,
Zhao Chao,
Fan Sigang,
Yan Lulu,
Wang Chengyang,
Qiu Lihua
Publication year - 2018
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.13705
Subject(s) - biology , vibrio harveyi , lateolabrax , transmembrane domain , complementary dna , immune system , microbiology and biotechnology , innate immune system , amino acid , proteobacteria , bacteria , gene , vibrio , biochemistry , genetics , fishery , fish <actinopterygii> , 16s ribosomal rna
Toll‐like receptors ( TLR s) play an indispensable role in fish immunity, being involved in pathogen recognition and the triggering of immune reactions. Here, a member of the TLR family, TLR 1, from Lateolabrax japonicus was characterized and its expression pattern and intracellular localization were analysed. The full‐length Lj TLR 1 cDNA (2,755 bp) was found to encode a polypeptide of 827 amino acids. The deduced amino acid sequence contained three main structural domains: an extracellular leucine‐rich repeat domain, a transmembrane domain and a Toll/ IL ‐1 receptor domain. Tissue distribution analysis indicated that Lj TLR 1 was expressed in all of the examined tissues to varying degrees, with the highest levels being measured in the head kidney. In order to assess the antibacterial functions of Lj TLR 1 during infection, the pathogenic bacteria Vibrio harveyi and Streptococcus agalactiae were used. Lj TLR 1 was significantly upregulated in the three immune organs (the head kidney, spleen and liver) following bacterial stimulation, and its expression was detected 6 hr after initial exposure. In mRNA in situ hybridization experiments, positive signals were more numerous in the treatment group than the control group, verifying the expression patterns observed. Assessment of the intracellular localization of Lj TLR 1 revealed it to be present in the cytoplasm. These results indicate the potential role of Lj TLR 1 in immune responses to bacterial infection. This study enriches our knowledge of L. japonicus immune genes and provides a theoretical basis for further research concerning the antibacterial functions of fish TLR s during infection.