1. Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
2. Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
3. Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
4. Department of Statistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
5. Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.