Hormone induces binding of receptors and transcription factors to a rearranged nucleosome on the MMTV promoter in vivo.

摘要: Hormonal induction of the mouse mammary tumour virus (MMTV) promoter is mediated by interactions between hormone receptors and other transcription factors bound to a complex array sites. Previous results suggested that access these sites modulated their precise organization into positioned regulatory nucleosome. Using genomic footprinting, we show MMTV DNA rotationally phased in intact cells containing either episomal or chromosomally integrated proviral fragments. Prior there no evidence for promoter. Following progesterone with high levels receptor, footprinting detects simultaneous protection over binding receptors, NF-I octamer proteins. Glucocorticoid progestin leads characteristic chromatin remodelling independent ongoing transcription. The centre nucleosome becomes more accessible DNase I restriction enzymes, but limits are unchanged 145 bp core region remains protected against micrococcal nuclease digestion. Thus, covering neither removed nor shifted upon induction, all relevant bind surface rearranged Since cannot simultaneously free DNA, maintainance may be required contiguous