1. Departments of Cell Biology and Orthopedics, Yale University School of Medicine, New Haven, Connecticut 06510
2. Metabolic Unit, Kaplan Medical Center, Rehovot, Israel
3. Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
4. Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
5. Department of Veterinary Resources, The Weizmann Institute of Science, Rehovot 76100, Israel