1. Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030.
2. Department of Medical Genetics, Haartman Institute, University of Helsinki, 00290 Helsinki, Finland.
3. Research Programs Unit, Molecular Neurology, University of Helsinki, 00290 Helsinki, Finland.
4. Cancer Gene Therapy Group, Molecular Cancer Biology Research Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, 00290 Helsinki, Finland.
5. Howard Hughes Medical Institute, Houston, TX 77030.