1. Departments of Pediatrics (K.G.H., Q.L., S.Y., F.S.F., S.H.H.), University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
2. the Laboratories for Reproductive Biology (K.G.H., Q.L., P.S., G.G., R.S., R.T.R., M.G.O., P.P., F.S.F., S.H.H.), University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
3. the State Key Laboratory of Molecular Biology (Q.L., Y.-L.Z.), Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
4. Cell and Developmental Biology (P.S., G.G., R.T.R., M.G.O., P.P.), University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599