Affiliation: | University of California, Santa Cruz;aHoward Hughes Medical Institute, Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309;bDepartment of Neurology, Massachusetts General Hospital, Boston, MA 02114;cHoward Hughes Medical Institute, Harvard Stem Cell Institute and Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 |