1. Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109 (E.N.); Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (A.Y.C.); and Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7–3–1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan (T.U.)