作者单位:Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390[1]Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, 4056 Basel[2]Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, United States[3]Howard Hughes Medical Institute, Department of Microbiology and Immunology, University of[4]