1. Molecular Endocrinology Group (P.J.O., J.H.D.B, S.S., G.R.W.), Division of Medicine and Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Campus, London, W12 0NN, United Kingdom
2. Gene Regulation Section (H.Y., S.-y.C.), Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4264