1. Division of Molecular and Cellular Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
2. Department of Molecular Biology, Osaka Medical Center for Cancer and Cardiovascular Disease, Osaka 537-8511, Japan.
3. Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan.