(Cell Stem Cell 10, 759–770; June 14, 2012) This article has been retracted at the request of the authors. This article reports that protein kinase A (PKA) accelerates early phase differentiation of mouse embryonic stem cells through rapid epigenetic suppression of pluripotent genes with H3K9 histone methyltransferase G9a. We have recently learned that we cannot locate a cell line (tetCA−PKA/G9a cKO cells) described in Figure 5. An investigation was monitored by the director of the Center for iPS Cell Research and Application (CiRA), Kyoto University. Cell stocks labeled as “tetCA−PKA/G9a cKO cells” were found to be an unrelated cell line used in the lab at the same period. The construction process of “tetCA−PKA/G9a cKO cells” was not recorded in lab notebooks. Under these circumstances, we believe that the most responsible course of action is to retract the paper. We sincerely apologize to the scientific community for any inconvenience resulting from the publication and retraction of this manuscript.