Octamer displacement and redistribution in transcription of single nucleosomes.
Single nucleosomes were assembled on a 357bp DNA fragment containing a 5S RNA gene from sea urchin and a promoter for SP6 RNA polymerase, and were fractionated as a function of their positions by gel electrophoresis. Transcribed nucleosome positions were detected by observing band disappearance in gels, which in turn provided evidence for the displacement of the histone octamer upon transcription. Differential band disappearance showed that nucleosomes closer to the promoter were harder to transcribe, and transcription was blocked when the nucleosome proximal boundary was at the start site. Nucleosomes located at discrete positions were also eluted from the gel bands and transcribed. In this case, new bands appeared as a consequence of octamer redistribution. Such redistribution occurred over all untranscribed positions, as well as over transcribed positions close enough to the promoter. Similar conclusions were derived from another previously investigated fragment containing a Xenopus 5S RNA gene.
O'Donohue
M F
MF
Institut Jacques Monod, Centre National de la Recherche Scientifique et Université Paris 7, France.
Duband-Goulet
I
I
Hamiche
A
A
Prunell
A
A
D000818:Animals; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D015245:Deoxyribonuclease BamHI; D015252:Deoxyribonucleases, Type II Site-Specific; D004372:Ducks / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D018014:Gene Transfer Techniques; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D046911:Macromolecular Substances; D009707:Nucleosomes / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012341:RNA, Ribosomal, 5S / Q000235:genetics; D012617:Sea Urchins / Q000235:genetics; D014158:Transcription, Genetic; D014981:Xenopus / Q000235:genetics
D006657:Histones; D046911:Macromolecular Substances; D009707:Nucleosomes; D012341:RNA, Ribosomal, 5S; C070852:RNA polymerase SP6; D012321:DNA-Directed RNA Polymerases; D015245:Deoxyribonuclease BamHI; D015252:Deoxyribonucleases, Type II Site-Specific; C040158:GTAC-specific type II deoxyribonucleases