1. Department for Biochemistry, Children's Hospital; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
2. Institute of Biochemistry and Molecular Biology; University of Bonn; Nussallee 11 D-53115 Bonn Germany
3. Research Department Cell and Gene Therapy, Clinic for Stem Cell Transplantation; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
4. Center for Molecular Neurobiology Hamburg, ZMNH; University Medical Center Hamburg-Eppendorf; 20246 Hamburg Germany
5. Max Delbrück Center for Molecular Medicine; 13125 Berlin-Buch Germany
6. Department of Biochemistry and Molecular Cell Biology; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany