1. Department of Medical Biochemistry, Göteborg University, PO Box 440, SE 405 30 Göteborg, Sweden
2. Department of Genetics and Pathology, Rudbeck Laboratory, SE 751 85 Uppsala,Sweden
3. Department of Experimental Pathology, Lund University, SE 221 85 Lund,Sweden
4. Max Planck Institute for Biochemistry, Department of Molecular Medicine, Am Klopferspitz 18a, D-82152 Martinsried, Germany