1Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA 90095, USA
2Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California at Los Angeles, Los Angeles, CA 90095, USA
4Department of Biological Chemistry, University of California at Los Angeles, CA 90095, USA
6Howard Hughes Medical Institute (HHMI), University of California at Los Angeles, Los Angeles, CA 90095, USA
