1. Department of Dermatology, Jefferson Medical College, and Section of Molecular Dermatology, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA 19107, U.S.A.
2. Department of Biochemistry and Molecular Biology, Jefferson Medical College, and Section of Molecular Dermatology, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA 19107, U.S.A.
3. Department of Anatomy and Histology, and The Research Center for Oral Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, U.S.A.