1. Department of Embryonic Stem Cell Research; Institute for Frontier Medical Sciences; Kyoto University; 53 Kawahara-cho, Shogoin, Sakyo-ku Kyoto 606-8507 Japan
2. Institute for Integrated Cell-Material Sciences (WPI-iCeMS); Kyoto University; Ushinomiya-cho, Yoshida, Sakyo-ku Kyoto 606-8501 Japan
3. Department of Development and Differentiation; Institution for Frontier Medical Sciences; Kyoto University; 53 Kawahara-cho, Shogoin, Sakyo-ku Kyoto 606-8507 Japan