Fig. 1

Traditional model of direct co-activator recruitment and an alternative model postulating initial promoter nucleosome distortion followed by co-activators and basal factors recruitment and assembly of transcription initiation complex. a The direct-recruitment model suggests numerous physical interaction of AD with multiple co-activators and transcription initiation complex components, thus bringing them to the promoter. b In the promoter nucleosome-distortion model, the AD modifies promoter nucleosome structure triggering an action of enzymatic activities, thus further affecting nucleosome structure, which leads to the nucleosome translocation and promoter opening. After this stage, the AD in cooperation with freely exposed DNA promoter elements recruits and stabilizes at the promoter the transcription initiation complex components