1. Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 598401;
2. Department of Biochemistry, University of Kentucky, Lexington, Kentucky 40536-00842;
3. Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 602083;
4. Mammalian Genetics Laboratory, ABL Basic Research Program, NCI Frederick Cancer Research and Development Center, Frederick, Maryland 217024; and
5. The Jackson Laboratory, Bar Harbor, Maine 046095