Affiliation: | aDepartment of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139;;bDepartment of Biochemistry and;eDepartment of Bacteriology, University of Wisconsin, Madison, WI 53706;;cHoward Hughes Medical Institute, Department of Biomedical Engineering, Center for BioDynamics, and Center for Advanced Biotechnology, Boston University, Boston, MA 02215; and;dBoston University School of Medicine, Boston, MA 02118 |