Regulation of Eucaryotic Transcription by DNA-binding Proteins

Primary controlling elements of the transcriptional activity in eucaryotes are specific DNA-binding proteins. They bind cis-acting DNA elements and have a specific influence on the initiation of transcription. 

As in procaryotes, there are transcription activating proteins, the transcriptional activators, as well as proteins which inhibit transcription, the transcriptional repressors. Of the two classes, the activators are the most extensively studied and characterized. The mechanism of eucaryotic repressors has only been clarified in a few cases. 

It is generally true that that eucaryotic transcriptional activators act via direct or indirect protein-protein contacts with the transcription apparatus. In this context the definition of the transcription apparatus is rather broad it includes the basal apparatus as well as proteins which act as co-activators or mediators (see 1.4.3.2). 

For a DNA-binding protein to engage in regulation of activation of transcription it must possess the following functions  

The activators of transcription have been studied and characterized the most extensively and will be discussed first. 

---