1. Department of Cell Genetics, Genentech, South San Francisco, CA 94080.
2. Department of Molecular Biology, Genentech, South San Francisco, CA 94080, USA.
3. Department of Pharmacology, Genentech, South San Francisco, CA 94080, USA.
4. Department of Endocrine Research, Genentech, South San Francisco, CA 94080, USA.