Molecular Cloning and Functional Characterization of Galectin-1 in Yellow Drum ().

Galectins are proteins that are involved in the innate immune response against pathogenic microorganisms. In the present study, the gene expression pattern of (named as ) and its function in mediating the defense response to bacterial attack were investigated. The tertiary structure of Gal-1 protein consists of homodimers and each subunit has one carbohydrate recognition domain. Quantitative RT-PCR analysis indicated that was ubiquitously distributed in all the detected tissues and highly expressed in the swim-bladder of , and its expression could be upregulated by the pathogenic attack in the brain. Expression of Gal-1 protein in HEK 293T cells was distributed in the cytoplasm as well as in the nucleus. The recombinant Gal-1 protein by prokaryotic expression could agglutinate red blood cells from rabbit, , and . The agglutination of red blood cells by the recombinant Gal-1 protein was inhibited by peptidoglycan, lactose, D-galactose, and lipopolysaccharide in certain concentrations. In addition, the recombinant Gal-1 protein agglutinated and killed some gram-negative bacteria including , , , , , and . These results set the stage for further studies of Gal-1 protein in the innate immunity of .