Fig. 4. Loss of PADI6 alters the levels and localization of ribosomal protein S6 and affects protein synthesis in two-cell embryos. (A) PADI6 (P6) colocalizes with S6 at the non-apposed cortical regions of Padi6^+/+two-cell embryo blastomeres, whereas S6 is absent from the embryonic cortex in Padi6^-/- two-cell embryos (arrows and B). (C) Phalloidin staining reveals that the cortical actin network is not disrupted in Padi6^-/- two cell embryos. (D) Western blot analysis of protein extracts indicates that S6 levels are reduced in Padi6^-/- two-cell embryos. (E) Fluorographic analysis of [³⁵S]methionine labeled proteins indicates that specific mRNAs are translated at different efficiencies in Padi6^-/- two-cell embryos. Asterisk indicates putative spindlin protein. (F) Confocal immunofluorescence analysis confirms that spindlin expression is upregulated in Padi6^-/- two-cell embryos. These experiments were repeated three times.