1. Department of Biochemistry & Molecular Biology (Z.H., D.D., M.F.W.), University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030
2. The Institute of Comparative Medicine (P.J.O.), University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom
3. Laboratory for Experimental Medicine and Endocrinology (K.D.G., G.V.), Catholic University of Leuven, B-3000 Leuven, Belgium
4. Department of Reproductive Medicine (M.F.W.), The University of California, San Diego, California 92093