Chipping away at the embryonic stem cell network

Abstract

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 co-occupancy 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.