Chipping away at the Embryonic Stem Cell Network

Critical transcription factors, notably OCT4, SOX2, and NANOG, are necessary to maintain self-renewal and pluripotency, two properties characteristic of embryonic stem (ES) cells. By analyzing the genome-wide localization of these factors at promoter regions in human ES cells, Boyer et al. (2005) demonstrate frequent promoter cooccupancy at numerous target genes. As they discuss in this issue of Cell, their findings indicate the presence of a complex network of autoregulatory and feedforward loops in human ES cells