ESCs (Embryonic stem cells) are Pluripotent cells derived from the ICM (Inner Cell Mass) of Blastocyst-stage embryos. These cells have two distinctive properties: an unlimited capacity for Self-renewal and Pluripotency. The capability for Self-renewal and the Pluripotency of ESCs seem to be under the control of multiple transcriptional factors, most common among them being Nanog (Nanog homeobox), Oct4 (Octamer Binding Transcription Factor-4) and SOX2 (SRY (Sex Determining Region-Y) Box-2). Functions of these transcription factors depend on the stage of development of a Pluripotent cell, indicating that these factors function in combination with other processes. The activity of these transcription factors also depends on the accessibility of their target genes, which are made accessible by the modification of their DNA, histones, or chromatin structure. These transcription factors activate or repress patterns of gene expression that mediate phenotypic changes during Stem Cell differentiation (Ref.1 & 2). |