1. Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, NIH, Frederick, Maryland, USA
2. Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
3. Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
4. Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
5. Li Ka Shing Applied Virology Institute, University of Alberta, Edmonton, Canada