1. Division of Virology; Aichi Cancer Center Research Institute; Nagoya 464-8681 Japan
2. Department of Virology; Nagoya University Graduate School of Medicine; Nagoya 466-8550 Japan
3. Division of Genetics; Kobe University School of Medicine; Kobe 650-0017 Japan
4. Department of Oncology, Graduate School of Pharmaceutical Sciences; Nagoya City University; Nagoya 467-8603 Japan