1. Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960–1295, Japan.
2. Core Research for Evolutional Science and Technology, Japan Science and Technology Cooperation, Kawaguchi 332-0012, Japan.
3. Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama 484-8506, Japan.
4. Department of Anatomy, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan.
5. Neurovirology Laboratory, Department of Virology 1, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
6. Present address: Department of Medical Pharmacy, Faculty of Pharmacy, Yasuda Women's University, Hiroshima 731-0153, Japan.
7. Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo 183-8526, Japan.