Gene repressor proteins which inhibit the transcription of particular genes in eukaryotes also exist. They may act by binding either to control parts within the promoter region near the gene or at sites located a long distance away from the gene, called as silencers.  The repressor protein should inhibit transcription directly. One instance is the mammalian   thyroid   hormone   receptor   that,   in the absence   of   thyroid   hormone   represses   transcription   of   the   goal   genes. Furthermore, other repressors inhibit transcription by blocking activation.  This can be get  in one of several  ways:  by blocking  the DNA  binding  site for an activator  protein, through binding to and masking  the activation  domain of the activator  factor,  or  by  forming  a  non-DNA  binding  complex  with  the  activator protein. Several instance of every mode of action are known.