1. Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
2. Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
3. Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA.
4. Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94704, USA.
5. Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
6. Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.