1. The Plant Molecular and Cellular Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
2. Department of Informatics, J. Craig Venter Institute, La Jolla, California 92037, USA
3. Department of Pathology, University of California San Diego, La Jolla, California 92093, USA
4. Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, California 92037, USA