However, fragments of native activator proteins have been described.

Enhancers do not act on the promoter region itself, but are bound by activator proteins.

These activator proteins interact with the mediator complex, which recruits polymerase II and the general transcription factors which then begin transcribing the genes.

This is done by binding (dimerization) with the AP1 (activator protein 1) to give a primary transcript that is 3' polyadenylated and 5' capped.

Ligands that bind to deactivate activator proteins are not, in the technical sense, classified as inducers, since they have the effect of preventing transcription.

It was eventually determined that GM2 gangliosidosis could be caused by mutations on three distinct genes, one of which was an activator protein.

Other regulatory genes code for activator proteins.

With positive control, an activator protein stimulates transcription by binding to DNA (usually at a site other than the operator).

In positive inducible operons, activator proteins are normally unable to bind to the pertinent DNA.

In positive repressible operons, the activator proteins are normally bound to the pertinent DNA segment.