Gene "bookmarking" regulates the fate of stem cells

A protein that stays attached on chromosomes during cell division plays a critical role in determining the type of cell that stem cells can become. The discovery, made by EPFL scientists, has significant implications for stem cell biology and their use in medicine. When cells divide, DNA is neatly wrapped up into chromosomes, and the normal expression of genes into proteins stops until the new cells are formed. However, some proteins that regulate gene expression stay attached to the chromosomes and 'bookmark" specific genes for the next generation of cells. These proteins are called 'transcription factors', and are important in embryonic stem cells because they determine what types of cells they can grow - or differentiate - into. EPFL scientists have now discovered that a transcription factor that is heavily involved in maintaining embryonic stem cells and controls their differentiation into stem cells of the brain and spinal cord also bookmarks genes during cell division. The study, published in Genes & Development , has significant implications for our understanding of stem cell biology and differentiation.