Isolation of gamma-interferon-inducible lysosomal thiol reductase (GILT) from the Yangtze finless porpoise

In this study, we isolated the cDNA of a gamma-interferon-inducible lysosomal thiol reductase (GILT), which is critical for innate immune regulation, from the Yangtze finless porpoise (FpGILT). This gene encoded a protein with 244 amino acids and a predicted molecular weight of 28 kDa. The amino acid sequence of FpGILT includes an active-site CXXC motif, a GILT signature sequence, CQHGX2ECX2NX4C, and three N-linked glycosylation sites. Phylogenetic analysis showed that FpGILT and other GILT family members were derived from a common ancestor and finless porpoises are closely related to artiodactyla. Recombinant protein (FpsGILT) was then efficiently expressed and purified, and thiol reductase activity assays suggested that FpGILT catalyses disulfide bond reduction. These findings provide a basis for understanding the characteristics of immunity in the finless porpoise and other aquatic mammals.