1. Departments of Medicine (C.J.D., M.-Y.C., C.K.G., J.L.W.)University of California, San Diego, La Jolla, California 92093;
2. Howard Hughes Medical Institute (G.D.B., M.D., R.M.E.), Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037
3. Cellular and Molecular Medicine (S.H., C.K.G.), University of California, San Diego, La Jolla, California 92093;