1. Pennington Biomedical Research Center/Louisiana State University (D.C.A., J.M., R.L.M., J.Y., A.A.B.), Baton Rouge, Louisiana 70808
2. Department of Biological Sciences (J.M.S.), Louisiana State University, Baton Rouge, Louisiana 70803
3. Amgen Inc. (A.W.B., W.G.R.), Thousand Oaks, California 91320