1. Graduate School of Biostudies, Kyoto University 1 , Kyoto 606-8501, Japan
2. Institute for Integrated Cell-Material Sciences (KUIAS-iCeMS), Kyoto University 2 , Kyoto 606-8501, Japan
3. Nagoya University Graduate School of Medicine 3 Department of Anatomy and Cell Biology , , Nagoya 466-8550, Japan
4. Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 4 Department of Human Morphology , , Okayama 700-8558, Japan
5. Jichi Medical University 5 Department of Anatomy, Division of Histology and Cell Biology , , Shimotsuke 329-0498, Japan
6. Division of Ultrastructural Research, National Institute for Physiological Sciences 6 , Okazaki 444-8585, Japan