1. Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
2. Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA.
3. Department of Cell and Tissue Biology, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94143, USA.
4. Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.