Transglutaminase orthologues in medaka fish - biochemical characterization and establishment of gene-deficient mutants

By genome analysis, seven homologous genes (orthologues) of human transglutaminases (TGases) have been identified in medaka fish (Oryzias latipes), some of which clearly corresponded to Factor XIII, TG1, and TG2. The enzymatically active-recombinant proteins for these medaka TGases have been successfully produced in bacteria or baculovirus-infected insect cell systems. Specific antibodies have been prepared and used in immunohistochemical analyses to reveal tissue distribution. Furthermore, gene-deficient medaka mutants for the genes encoding Factor XIII and TG1 have been established together with analysis of their phenotypes. Retarded cross-linking of fibrin and higher sensitivity to osmolality are observed when each gene is knocked-out. In this review, we summarize these biochemical features and the phenotypes of these gene-deficient fish. •Medaka fish are useful research model to study gene relevance in physiology and disease.•Medaka orthologues for human TGases have been identified.•The primary structures and tissue distributions of medaka TGases have been clarified.•TGase deficient medaka have been established with distinct phenotypes.