1. Laboratory of Embryonic Stem Cell Research, Stem Cell Research Center, Kyoto University, Kyoto, Japan
2. Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
3. Department of Development and Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
4. Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan