1. Baylor College of Medicine, Department of Molecular Virology and Microbiology, One Baylor Plaza, Houston, Texas 77030
2. University of Texas, Health Science Center, Department of Integrative Biology and Pharmacology, 6431 Fannin, Houston, Texas 77030
3. INSERM UMR538, UPMC, CHU St. Antoine, 27 rue Chaligny, 75014 Paris, France
4. National Institute of Genetics, Department of Cell Genetics, 1111, Yata, Mishima, Shizuoka 411-8540, Japan