Control of transcription initiation.

ABSTRACT

Mechanism of control of transcription initiation have expanded far beyond the classical operon concept. Control elements are multipartite and well separated from each other. The trans-factors bound to these sites make contacts with RNA polymerase promoter complexes by DNA bending or looping to influence the initiation event. Activators and repressors are like two faces of the same coin and their function depends on the site of action, mode of interaction with DNA and also the nutritional status of the cell.