National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development - Molecular Medicine Branch, University of Pennsylvania - Department of Pathology and Laboratory Medicine, University of Pennsylvania - Department of Biochemistry and Biophysics, Utah State University - Institute for Antiviral Research, National Institutes of Health, National Cancer Institute - Urologic Oncology Branch and National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development - Molecular Medicine Branch