Molecular Cloning， Identification and Preliminary Function Study of Galectin-3 Gene in Ayu (Plecoglossus altivelis)

Abstract: Galectin-3 (Gal3)， a member of lectins， plays an important role in mammalian innate immunity. However， little is known about fish Gal3. In this paper， the nucleotide sequence of a full-length cDNA clone for ayu (Plecoglossus altivelis) Gal3 (PaGal3) gene， 2 009 nucleotides in length， was determined by de novo transcriptome sequencing of ayu monocytes/macrophages. It contained a completely open reading frame (ORF) which encoded a polypeptide of 380 amino acids with a calculated molecular weight of 38.28 kDa and a theoretical isoelectric point (pI) of 4.58. Multiple alignment showed that PaGal3 had the typical characters of animal galectin (Gal) family. Phylogenetic tree analysis revealed that PaGal3 was most closely related to that of rainbow trout (Oncorhynchus mykiss) with 77% amino acid sequence identity， and the relationships of the different Gal3 coincided well with the widely accepted evolutionary relationships of their organisms. After Vibrio anguillarum infection， PaGal3 mRNA expression of liver， kidney， spleen and monocytes/macrophages of ayu increased significantly， which was deter中 mined by Real-time quantitative PCR (RT-qPCR) method. When we used antibody to block PaGal3， the phagocytic and bacterial killing activities of ayu monocytes/macrophages both decreased significantly， suggesting that PaGal3 could enhance the functions of monocytes/macrophages. In summary， PaGal3 gene is closely related to fish immune response， and may play an important role in the inflammatory immune response of ayu.

CSTR: 32200.14.cjcb.2015.03.0006