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Molecular cloning and characterization of Toll-like receptor 14 in Japanese flounder, Paralichthys olivaceus.

Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo, 108-8477, Japan.
Fish &amp Shellfish Immunology (Impact Factor: 3.03). 01/2011; 30(1):425-9. DOI: 10.1016/j.fsi.2010.08.005
Source: PubMed

ABSTRACT Toll-like receptors (TLRs) are essential for activation of the innate immune system in response to invading pathogens. TLR14, which is unique to fish, has been identified in several fish species, but its function is unclear. In this study, Japanese flounder (Paralichthys olivaceus) TLR14 gene (JfTLR14) was cloned and its expression profiles were analyzed after infection with viral hemorrhagic septicemia virus, gram-positive Streptococcus iniae and gram-negative Edwardsiella tarda. The coding region of JfTLR14 cDNA was 2,607 bp, encoding 878 amino acid residues. JfTLR14 was highly expressed in head kidney of healthy flounder. In response to infection with VHSV and S. iniae, the JfTLR14 gene was up-regulated at only 1 day post-infection (dpi). However, E. tarda infection increased JfTLR14 gene expression from 1 to 6 dpi. These results imply that JfTLR14 participates more in the immune response against E. tarda infection than in the immune responses to other pathogen infections.

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    • "In the Japanese flounder, TLR14, which has not yet been detected in mammals, is induced more strongly after E. tarda infection than after Streptococcus iniae infection or virus infection (Hwang et al., 2011). Recently, expression of TLR5S was shown to be induced during pathogen infection of Atlantic salmon (Tsoi et al., 2006) and olive flounder (Moon et al., 2011), suggesting that TLR5S is an important PRR that responds to bacterial infection and regulates acute immunity in fish. "
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    • "There are no homologs of mammalian TLR6 or -10 in teleosts [24] [25] [33], indicating that they evolved later (Table 1) [25] [33]. The fish TLR14 genes have been classified as homologs of the mammalian TLR2 subfamily because TLR14 is located closest to the TLR2 cluster, suggesting that it evolved from an ancestor of TLR2 prior to the divergence of agnathans and teleosts [34] [35]. Thus, TLR14 might be a functional substitute for mammalian TLR6 and -10. "
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