SRY (sex determining region Y)-box 2, also known as SOX2, is a transcription factor that is essential to maintain self-renewal of undifferentiated embryonic stem cells. Sox2, Oct-4 and Nanog co-operate in this network, and siRNA knockdown of either Sox2 or Oct-4 results in loss of pluripotency. POU5F1/OCT4, SOX2, MYC/c-Myc and KLF4 are the four Yamanaka factors. When combined, these factors are sufficient to reprogram differentiated cells to an embryonic-like state designated iPS (induced pluripotent stem) cells
