sentences:  For example, by binding to a site on DNA that overlaps with the binding site of an activator, a repressor can inhibit binding of the activator.But more frequently, eukaryotic repressors inhibit the function of an activator by masking its activating domain, preventing its nuclear localization, promoting its degradation, or inactivating it through chemical modifications.Repressors can directly inhibit transcription initiation by binding to a site upstream of a promoter and interacting with the transcriptional machinery.