H3K27me3

H3K27me3 is a specific chemical modification found on histone proteins, which are part of our DNA structure. These modifications act like signals that can turn genes off or "silence" them, controlling how cells behave. In particular, H3K27me3 involves adding three methyl groups to the 27th amino acid (lysine) on histone H3. This mark is associated with the long-term repression of genes, often important in development and maintaining cell identity. Essentially, H3K27me3 helps cells remember which genes should stay inactive so they can function properly.