1. H. Dudek, S. R. Datta, M. E. Greenberg, Division of Neuroscience, Department of Neurology, Children's Hospital, and Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
2. T. F. Franke, Montreal Neurological Institute, McGill University, PQ H3A 2B4, Canada; and Division of Signal Transduction, Beth Israel Hospital, and Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
3. M. J. Birnbaum, Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
4. R. Yao and G. M. Cooper, Division of Molecular Genetics, Dana-Farber Cancer Institute, and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
5. R. A. Segal, Department of Neurology, Beth Israel Hospital, and Harvard Medical School, Boston, MA 02115, USA.
6. D. R. Kaplan, Montreal Neurological Institute, McGill University, PQ H3A 2B4, Canada.