1. Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi 329-0498, Japan
2. University Farm, Department of Agriculture, Utsunomiya University, 443 Shimokomoriya, Mouka-shi, Tochigi 321-4415, Japan
3. CREST, Japan Science and Technology Agency, 5-3 Yonbancho, Chiyoda-ku, Tokyo 102-8666, Japan