1. Department of Pediatrics, Graduate School of Medicine,
2. Laboratory of Embryonic Stem Cell Research, Stem Cell Research Center, Institute for Frontier Medical Sciences, and
3. Department of Medicine, Boston University School of Medicine, MA;
4. Research Center for Animal Life Science, Shiga University of Medical Science, Japan;
5. Division of Genetics, Institute of Medical Science, University of Tokyo, Japan
6. Department of Development and Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Japan;