Transcription Factors: Proteins that control which genes are turned on or off by binding to nearby DNA. These would be other members of our police force directing different types of traffic.
Coactivators: Proteins that increase gene expression by interacting with transcription factors or RNA polymerase II – they're like dispatchers sending more cars onto our roadways.
Silencing Mediator for Retinoid or Thyroid-hormone receptors (SMRT): An example of a corepressor that regulates genes responsive to thyroid hormone – a specialized supervisor for certain types of traffic.