Analyzing the contributions of chromatin structure in nuclear hormone receptor activated transcription in vivo.

The authors have described three approaches for analyzing the chromatin architecture of a steroid-responsive promoter. Mnase allows one to map the positions of nucleosomes on the target gene. The more sensitive restriction enzyme hypersensitivity procedure permits detection of changes in chromatin architecture upon hormonal stimulation. Additional insight into transcriptional regulation of a gene can be obtained by using the related ExoIII footprinting protocol, which provides complementary data on transcription factor binding to chromatin templates. The use of these in vivo chromatin analysis techniques have provided evidence for a role of chromatin structure in regulation of transcription of steroid-responsive promoters including MMTV (2,7,10,14), tyrosine aminotransferase (15), TR beta A (16-19), and retinoic acid receptor beta (RAR beta) (20).