Essential for proliferation of the inner cell mass and trophectodermal cells in peri-implantation development. Mainly cytoplasmic from the 4-cell stage to the morula stage. Becomes nuclear at the blastocyst stage. In ES cells, found in both the nucleus and the cytoplasm. Transcriptionally activated at the 2-cell stage, peaks at the 4-cell stage and then gradually decreased until the blastocyst stage. The protein is detected from the 4-cell stage until the blastocyst stage. In blastocysts, expressed both by inner cell mass and trophectodermal cells (at protein level). Not detected in post-implentation, neither in fetal, nor adult tissues.