1. Gene Engineering Division, RIKEN (Institute of Physical and Chemical Research), BioResource Center, Tsukuba, Ibaraki 305-0074
2. Department of Medical Genetics, China Medical University, Shenyang 110001, People's Republic of China
3. Institute of Molecular and Cellular Bioscience, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
4. Dental Research Institute/Oral Biology and Medicine, School of Dentistry
5. Surgical Oncology, School of Medicine, University of California, Los Angeles, California 90095-1668