Molecular characterization of the lgals1 gene in large scale loach Paramisgurnus dabryanus

Galectins constitute a group of lectins with binding specificity for β-galactoside sugars. Galectin-1 is a prototype galectin and the multifunctionality of mammalian galectin-1s is well-known, but only a few of fish galectin-1s have been identified. In this study, we obtained the full-length cDNA and genomic sequence of the galectin-1 gene (designated as Pdlgals1) from large scale loach (Paramisgurnus dabryanus), performed phylogenetic analysis, and characterized the expression pattern and the transcriptional activity of its 5' flanking region. The Pdlgals1 gene contains 4 exons that encode a peptide of 132 amino acids with all the galectin signature motifs. Phylogenetic analysis and sequence alignment indicated that Pdlgals1 is a homologue of human LGALS1. RT-PCR and whole-mount in situ hybridization revealed that Pdlgals1 is mainly expressed in the skin, muscle, intestine and cavum oropharyngeum. Transcriptional activity assays demonstrated that the basal promoter of Pdlgals1 is located in a region from -500bp to its transcriptional start site. Potential binding sites for transcription factors including C/EBP, AP-1, GATA, Oct-1, δEF1, NF-κB, c-Myb, SP-1, AP-2, AML-1α, and AP-4 were identified in the basal promoter, suggesting that these factors are associated with the regulation of Pdlgals1. These results provided clues for further investigation of galectin-1 functions in loaches.