title: Nucleosomes inhibit the initiation of transcription but allow chain elongation with the displacement of histones.
abstract: Promoters were assembled in nucleosomes or ligated to nucleosomes and transcribed with SP6 RNA polymerase or with mammalian RNA polymerase II and accessory factors. Neither polymerase would initiate transcription at a promoter in a nucleosome, but once engaged in transcription, both polymerases were capable of reading through a nucleosome. In the course of readthrough transcription, the histones were displaced from the DNA, as shown by the exposure of restriction sites and by a shift of the template to the position of naked DNA in a gel. It may be true, in general, that processive enzymes will traverse regions of DNA organized in nucleosomes and displace histones.
mesh_terms: D000818:Animals; D002843:Chromatin / Q000502:physiology; D002874:Chromosome Mapping; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005786:Gene Expression Regulation; D006657:Histones / Q000502:physiology*; D009707:Nucleosomes / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D051381:Rats; D013698:Templates, Genetic; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases