Interaction between transcription regulatory regions of prolactin chromatin.

The regulation of transcription requires complex interactions between proteins bound to DNA sequences that are often separated by hundreds of base pairs. As demonstrated by a nuclear ligation assay, the distal enhancer and the proximal promoter regions of the rat prolactin gene were found to be juxtaposed. By acting through its receptor bound to the distal enhancer, estrogen stimulated the interaction between the distal and proximal regulatory regions two- to threefold compared to control values. Thus, the chromatin structure of the prolactin gene may facilitate the occurrence of protein-protein interactions between transcription factors bound to widely separated regulatory elements.