Stem cell regulation by polycomb repressors: postponing commitment.
Polycomb group proteins (PcGs) are involved in gene repression through chromatin modifications and required for the maintenance of both embryonic and adult stem cells. Genome-wide studies demonstrate that genes targeted by PcG are predominantly developmental transcription factors. In embryonic stem cells, these genes carry not only a repressive PcG mark but also an activating mark, resulting in so-called 'bivalent domains'. New data suggest that genes with bivalent domains are primed for differential expression upon differentiation. We propose that the resolution of a bivalent domain into either an active or repressed state constitutes a cell fate decision, and that by postponing these decisions PcG contributes to pluripotency.
Pietersen
Alexandra M
AM
Netherlands Cancer Institute, Molecular Genetics, P1, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. a.pietersen@nki.nl
van Lohuizen
Maarten
M
D000818:Animals; D019070:Cell Lineage; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins / Q000378:metabolism*; D013997:Time Factors
D063146:Polycomb-Group Proteins; D012097:Repressor Proteins