1. Department of Molecular Genetics, National Institute of Neuroscience, NCNP, Kodaira, Tokyo 187-8502, Japan;
2. Department of Molecular Biochemistry, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan;
3. Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037;,