Dr. Saburo Nagata
Research overview The South African clawed frog, Xenopus laevis, has been used as an excellent animal model in developmental biology. In addition to advantages in the classical experimental embryology, high fidelity expression of microinjected mRNA or cDNA made Xenopus one of the favorite species of modern developmental biologists. Using this frog, we have studied the roles of a group of lectins in innate immunity . Innate immunity is responsible for the front line of host defense system against invading pathogenic microbes and parasites. The basic molecular mechanisms of innate immunity have shown to be conserved among a wide range of divergent animal species and provide the foundation for evolution of acquired immunity in vertebrates. Recent studies have established that varieties of lectins, a group of proteins that recognize and bind to sugar chains, play important roles in pathogen recognition and effector functions in innate immunity. The XCGL (or X-lectin) family is a unique group of lectins found in several chordate species and Xenopus has six XCGL family lectins. Xenopus embryonic epidermal lectin (XEEL) is secretd from embrynic epidermis during a limited period after hatching while their adaptive immune system was still immature. A novel serum lectin XCL1 binds to Gram-negative and -positive bacteria and its serum content increases rapidly after intraperitoneal injection of the bacteria. Thus, XEEL and XCL1 may be involved in protecting embryos or frogs from pathogenic microorganisms. We are investigating the mechanisms of prodction and function of these lectins by molecular and cellular levels.
Department of Chemical and Biological Sciences
Faculty of Science
Japan Women's University