Histone methyltransferases (HMTs)

Histone methyltransferases (HMTs) are enzymes that add methyl groups to histone proteins, which are essential components of chromatin (the structure that packages DNA in cells). This methylation can influence how tightly or loosely the DNA is wrapped around histones, affecting gene expression. When genes are tightly packed, they are often silenced; when loosely packed, they can be activated. Thus, HMTs play a crucial role in regulating various biological processes, including development and responses to environmental changes, by controlling which genes are turned on or off in a cell.