Embryonic Stem Cells
Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocyst-stage embryos. The basic properties of ES cells, which distinguish them from all other organ-specific cells, include homeostatic self renewal and the ability to undergo multi-lineage differentiation in vitro and in vivo. True ES cells can be maintained as a pure population indefinitely in culture. Human ES cells are routinely assayed for the expression of well characterized protein and molecular markers of pluripotency including the transcription factors Oct 3/4, Sox2, c-Myc and Klf4.