From People - School of Science, The University of Tokyo
野中 勝 (のなか まさる)
NONAKA, Masaru
| Title | Professor |
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| Affiliation | Department of Biological Sciences (Zoological Science), Graduate School of Science |
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| Room | 312, Faculty of Science Bldg.2, 3F |
| TEL | +81-3-5841-7589 27589 (ext.) |
Research Field
Evolutionary Immunology
Research Subject
Origin and evolution of the complement system and the major histocompatibility complex (MHC)
Current Research
The mammalian complement system is a complex biological system being composed of more than 30 serum and cell surface proteins, and plays a central role in innate immunity. The main function of the complement system is to add a molecular tag to non-self particles, such as invading microbes. Molecular tagging is performed by covalent binding of C3, the central component of the complement system, and tagged microbes are eliminated from circulation by phagocytosis or complement-dependent cytolysis. Phylogenetic studies so far performed revealed that all jawed vertebrates, cartilaginous fish and higher vertebrates, have a well developed complement system similar to that of mammals. In contrast, composition and function of the complement system of jawless fish and invertebrates are still poorly understood. Although the C3 gene is not found in the D.melanogaster or C. elegans genomes, it is present in some Cnidaria. Thus, the C3 gene seems to have been established before the protostome/deuterostome divergence, and to have been lost in some invertebrate lineages. The objective of our research is to understand the origin and development of this intriguing biological system during the metazoa evolution. The human Major Histocompatibility Complex (MHC) is an about 4 Mb genomic region, containing more than 100 expressed genes. Many of these genes encode immunological molecules essential to both adaptive and innate immune systems. There are intriguing linkages of the functionally linked, but structurally unrelated genes in the mammalian MHC, which could be formed either by adaptive or accidental processes. Phylogenetic analysis of genome structure of the MHC can provide an insight into the evolutionary processes involved, and we are analyzing physical structure of the MHC of lower vertebrates, especially a bony fish, medaka. These analyses are expected to elucidate not only the specific evolutionary process of the MHC, but also the general evolutionary process of biological reaction systems.
Keywords
Complement, MHC, Molecular Evolution, Vertebrate, Innate Immunity, Adaptive Immunity, Medaka, Tunicate, Genome