The Cln3-CDK2 complex promotes transcription of S-phase genes by inactivating the transcriptional repressor Whi5. Tyrosine can also be inhibited at the transcriptional level by the TyrR repressor. DNA methylation is a powerful transcriptional repressor, at least in CpG dense contexts. It can also act as a transcriptional repressor. The cluster contains a transcriptional activator "qa-1F", a transcriptional repressor "qa-1S", and five structural genes. Lactose binds to the repressor protein and prevents it from repressing gene transcription. The image to the right demonstrates regulation by a repressor in the lac operon. The particular example of SINEs potentially recruit the YY1 polycomb transcriptional repressor is discussed above. In addition, the acetylation of p53 prevents its binding to the repressor Mdm2 on DNA. The Nanos protein is a translational repressor protein. This gene encodes one member of a family of translation repressor proteins. Hepatocellular carcinoma cell proliferation may arise from miR-21 interaction with MAP2K3, a tumor repressor gene. The balance between repressor and activator E2F regulate cell cycle progression. Cancers usually result from disruption of a tumor repressor or dysregulation of an oncogene. Deletion of the motif resulted in IcaR repressor accumulation and inhibition of biofilm development.