1. Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
2. 21st Century COE (Center of Excellence) Cell Fate Regulation Research and Education Unit, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
3. Global COE Cell Fate Regulation Research and Education Unit, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
4. Laboratory for Animal Resources and Genetic Engineering, Center for Developmental Biology (CDB), RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
5. Division of Integrative Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.