Characterisation of a chromatin fraction bearing pulse-labelled RNA. 1. Nascent RNA, RNA polymerase B and transcribed DNA sequence content.
We have further characterised a fraction of polynucleosomal chromatin from mouse cells which is enriched in transcribing regions, after separation by multistep partition in a dextran /poly(ethylene glycol) two-phase mixture [Faber, A. J. (1972) Methods Cell Biol. 16, 447--457]. This fraction contains an average of 16% of the total DNA and 63% of the 3-min pulse-labelled RNA in chromatin which, by a number of criteria, represents nascent RNA transcripts. Of the total transcribing RNA polymerase B molecules in chromatin, 52% are found in this fraction by titration with radioactive alpha-amanitin. About 28% of the single-copy DNA sequences in this fraction hybridise to nuclear polyadenylated RNA, compared with only 1.5% of the single-copy sequences in the remaining (nontranscribing) chromatin fraction.
D000818:Animals; D001483:Base Sequence; D002843:Chromatin / Q000302:isolation & purification*; D004247:DNA; D051379:Mice; D009693:Nucleic Acid Hybridization; D009707:Nucleosomes / Q000737:chemistry*; D012313:RNA / Q000032:analysis*; D012319:RNA Polymerase II / Q000032:analysis; D014158:Transcription, Genetic
D002843:Chromatin; D009707:Nucleosomes; D012313:RNA; D004247:DNA; D012319:RNA Polymerase II