Epigenetic modifications, such as DNA methylation and histone modification, play a significant role in gene expression regulation. These modifications are catalyzed by specific enzymes and can lead to changes in chromatin structure, making genes more or less accessible for transcription. For example, DNA methyltransferases add methyl groups to DNA, often leading to gene repression, while histone acetyltransferases add acetyl groups to histones, generally associated with gene activation.
