Stability and flexibility of epigenetic gene regulation in mammalian development.

Nature. 2007 May 24;447(7143):425-32.
Stability and flexibility of epigenetic gene regulation in mammalian development.
Reik W.
Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge CB22 3AT, UK. wolf.reik@bbsrc.ac.uk
During development, cells start in a pluripotent state, from which they can differentiate into many cell types, and progressively develop a narrower potential. Their gene-expression programmes become more defined, restricted and, potentially, 'locked in'. Pluripotent stem cells express genes that encode a set of core transcription factors, while genes that are required later in development are repressed by histone marks, which confer short-term, and therefore flexible, epigenetic silencing. By contrast, the methylation of DNA confers long-term epigenetic silencing of particular sequences--transposons, imprinted genes and pluripotency-associated genes--in somatic cells. Long-term silencing can be reprogrammed by demethylation of DNA, and this process might involve DNA repair. It is not known whether any of the epigenetic marks has a primary role in determining cell and lineage commitment during development.
PMID: 17522676 [PubMed - indexed for MEDLINE]

Link for Full Text: http://www.nature.com/nature/journal/v447/n7143/full/nature05918.html