1. Department of Oncology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2. Department of Cell Regulation, Medical Research Institute, Tokyo Medical Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
3. Department of Molecular Genetics, Institute for Liver Research, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan
4. Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852