[Objective] The paper aimed to clone the full length gene of Toll-like recep- tors （TLRs） in Japanese flounder （Paralichthys olivaceus）, and analyze their structural features and expression regularity. [Method] The full length cDNA sequence of Toll like receptor 1（TLR1） gene was identified from Japanese flounder head kidney by ho- mologous cloning and rapid amplification cDNA ends （RACE）. The bioinformatics and expression model of this gene was analyzed. [Result] The TLR1 cDNA was 2 947 bp, a 2 418 bp open reading frame （ORF）, encoding 805 amino acid （aa） residues, including signal peptide, six leucine-rich repeat（LRR） motifs, two transmembrane zones and one TolI/IL 1 receptor （TIR） domain. The molecular weight of the deduced protein was 91.15 KDa, and the isoelectric point was 6.49. The amino acid sequence of Japanese flounder TLR1 possessed 69%-35% identity with the TLRls of other verte- brates, further analysis showed that the TIR domain of Japanese flounder TLR1 shared 84%-62% identities with TIR domains in other vertebrates. Japanese flounder TLR1 protein firstly clustered with TLRls in Epinephelus coioides in the phylogenetic analysis. The transcription of Japanese flounder TLR1 was examined by real-time quantitative PCR, and its mRNA was mainly detected in liver, heart and spleen. [Conclusion] The results lay a foundation for further studying the functions of TLR1 and developing immune potentiator in Japanese flounder.
