By Stuart P. Atkinson
Gene by gene, we are beginning to unravel and understand those members of the pluripotency network which give embryonic stem cells (ESCs) their identity. Other than giving us an understanding of the molecular networks, signalling pathways and regulatory mechanisms which exist in ESCs, such knowledge is also allowing us to make more and more critical studies of induced pluripotent stem cells (iPSCs) to establish whether these are bona fide “replacements” for embryo derived pluripotent cells. To this end, the group of Huck-Hui Ng utilising genome wide RNAi screens have attempted to further identify genes and pathways present in ESCs, with more than 21,000 genes targeted. This study, published in Nature, initially used an OCT4-GFP reporter to establish a list of potentially important genes for ESC pluripotency, which showed enrichment for transcription and translation factors. Further protein-protein interaction analysis found components of the INO80 chromatin remodelling complex, the mediator complex, the COP9 signalosome, the TAF complex, the eukaryotic initiation factor complex and the spliceosome complex which had not been associated with important functions in hESC.