Peter et al's paper The pluripotency factor Nanog regulates pericentromeric heterochromatin organization in mouse embryonic stem cells was recently published in Genes and Development. This research, led by the Babraham Institute with collaborators in the UK, Canada and Japan, has revealed a new understanding of how an open genome structure supports the long-term and unrestricted developmental potential in embryonic stem cells. This insight provides new avenues for improving the quality and stability of embryonic stem cells – an essential requirement to fulfil their promise in regenerative medicine.
How our DNA is stored and packaged in the nucleus can be viewed as two different states: regions of the genome that are ‘open for business’ and can be actively read, and regions that are locked away by being tightly packed and inaccessible to the factors that read DNA.
The researchers looked in detail at the mysterious tightly packed portions of the genome, called constitutive heterochromatin. Previous research has shown that heterochromatin is maintained in an unusually open and uncompacted organisation in embryonic stem cells, which is different to all other cell types. It is thought that this rare form of genome architecture may contribute to keeping stem cells in an unspecialised state, still full of the potential to become any cell type in the body. Why heterochromatin is organised in this way in embryonic stem cells has previously been unknown.