1. Laboratory of Molecular Biology; Graduate School of Agricultural Science; Tohoku University; Tsutsumidori-amamiyamachi 1-1 Aoba-ku Sendai 981-8555 Japan
2. Graduate School of Frontier Biosciences; Osaka University; Yamadaoka 1-3 Suita Osaka 565-0871 Japan
3. Department of Biochemistry; Graduate School of Medicine; Tohoku University; Seiryo-cho 2-1 Aoba-ku Sendai 980-8575 Japan