1. Committee on Neurobiology, University of Chicago, Chicago, IL 60637, USA
2. Department of Pathology, University of Chicago, Chicago, IL 60637, U.S.A.
3. Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A.
4. Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, U.S.A.
5. Department of Human Genetics, University of Chicago, Chicago, IL 60637, U.S.A.
6. Department of Biochemistry, Brandeis University, Waltham, MA 02453, U.S.A.