Corepressor (genetics)

A corepressor is a protein that decreases gene expression by binding to a transcription factor which contains a DNA binding domain. The corepressor is unable to bind DNA by itself. The coactivator can repress transcriptional initiation by recruiting histone deacetylases which catalyze the removal of acyl groups from lysine residues. This increases the positive charge on histones which strengthens in the interaction between the histones and DNA, making the later less accessible to transcription.