1. Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
2. School of Systems Biological Science, Soongsil University, Seoul 156-743, Republic of Korea
3. Department of Veterinary Physiology, College of Veterinary Medicine, Biosafety Research Institute, Chonbuk National University, Jeonju 561-756, Republic of Korea