Affiliation: | Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-04601.; Institute of Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, New York 10029-65742.; Dipartimento di Biologia, Universita Degli Studi di Padova, Padova, Italy4.; and Institut für Klinishe und Molekulare Virologie, Erlangen, Germany3. |