1. DNA Damage Response Network Center, Chosun University, Kwangju 501-709, Korea.
2. Department of Pharmacology, School of Medicine, Chosun University, Gwangju 501-759, Korea.
3. Department of Anatomy, School of Medicine, Chosun University, Gwangju 501-759, Korea.
4. Department of Anatomy, School of Medicine, Jeju National University, Jeju 690-756, Korea.