Hirohide Saito1, Yohei Yokobayashi2. 1. Department of Life Science Frontiers, Center for iPS Cell Research and Application (CiRA), Kyoto University, 53 Kawahara-cho, Shogoin, Sakyot-ku, Kyoto, 606-8507, Japan. Electronic address: hirohide.saito@cira.kyoto-u.ac.jp. 2. Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan. Electronic address: yohei.yokobayashi@oist.jp.