DNA, the hereditary material, interacts with proteins in the nuclei of cells to form a tightly packed complex with proteins, which is referred to as “chromatin.” The molecular architecture of the chromatin regulates access to genes, and therefore determines which genes can be activated in different cell types. Various chemical modifications of proteins called histones—which play a decisive role in the structuring of chromatin—serve as markers that can either activate or inhibit gene expression. How these epigenetic modifications are regulated during development, and in other contexts, is incompletely understood. Now researchers led by LMU molecular biologist Ralph Rupp have shown that the process of cell division itself can have an impact on which modifications become dominant. In rapidly dividing cells, levels of inhibitory modifications are reduced, increasing the probability of silenced genes to be reactivated. This phenomenon occurs in embryonic cells, and very probably in adult stem cells and precursor cells, as Rupp and his colleagues report in the journal PLOS Biology.
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Source: Phys.org