1. Laboratory of Animal Breeding and Reproduction, Division of Animal Science, Faculty of Agriculture, Utsunomiya University, Tochigi 321-8505, Japan
2. Center for Bioscience Research and Education, Utsunomiya University, Tochigi 321-8505, Japan
3. Department of Biochemistry, Keio University School of Medicine, Tokyo160-8582, Japan
4. Medical Education Center, Keio University School of Medicine, Tokyo 160-8582, Japan
5. Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
6. Present: Department of Molecular Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan