1. Department of Biotechnology, Graduate School of Agriculture and Life Sciences, the University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
2. Department of Bioactive Molecules, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan
3. Kitasato Institute for Life Sciences, Kitasato University, Sagamihara-shi, Kanagawa 228-8555, Japan
4. Department of Computational Biology, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa-shi, Chiba 277-8561, Japan