G9a

G9a is an epigenetic protein that plays an important role in regulating gene expression by modifying the structure of chromatin, the material that makes up chromosomes. Specifically, G9a is a histone methyltransferase, which means it adds chemical modifications (methyl groups) to histone proteins. Histones are the proteins around which DNA is coiled, and modifications to histones can either promote or inhibit gene expression, depending on the location and type of modification. G9a primarily adds methyl groups to histone H3 at a specific location called lysine 9 (hence the name G9a). This modification, known as H3K9me2, is associated with a more compact chromatin structure that typically represses gene expression. Therefore, G9a is often considered a gene silencer. G9a has been implicated in a variety of biological processes, including embryonic development, stem cell differentiation, and cancer.