1. Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Faculty of Medicine; The University of Tokyo; Bunkyo-Ku Tokyo 113-0033 Japan
2. Animal Resource Development Unit; Division of Bio-Function Dynamics Imaging, RIKEN Center for Life Science Technologies; Kobe Hyogo 650-0047 Japan
3. Genetic Engineering Team, Division of Bio-Function Dynamics Imaging; RIKEN Center for Life Science Technologies; Kobe Hyogo 650-0047 Japan