[Increase in the number of repeating sequences of DNA in transcriptionally active sites of rat genome induced by cortisol and phenobarbital].
The effects of transcription inducers, e. g. cortisol, phenobarbital and 3-acetate-16 alpha (beta)-isothiocyano-pregnenolone (AIP), which, similar to phenobarbital, activates the multifunctional oxidase system, on the nucleotide sequence arrangement in the DNA fractions corresponding to functionally different sites of the genome, were investigated. Three DNA fractions were isolated from rat liver cells, using different concentrations of NaCl and different pH values of aqueous solutions of phenol used for deproteination. The DNA fraction I extracted with 1 M NaCl and phenol (pH 6.4) down to the water phase contains 12-14% of non-hydrolyzed by hybrid RNA RNAase, is rich in unique sequences, makes up to about 20% of the genome and probably corresponds to the transcriptionally active sites of chromatin DNA. The DNA fraction II extracted by 0.14 M NaCl and "alkaline" phenol (pH 8.5) makes up to 70% of total cellular DNA, in which the hybrid RNA content does not exceed 2%. The amount of weakly extractable and, possibly, membrane-bound DNA III does not exceed 10% of total DNA content. During induction of transcription the number of repeating sequences is increased by about 10% in DNA I and is simultaneously decreased in DNA III. This can both be due to the arrangement of sequences between chromatin fractions corresponding to membrane DNA and the transcriptionally active sites of the genome. Hybridization of [3H]rRNA demonstrated that the contribution of ribosomal genes to the above changes in the arrangement of sequences in DNA fractions under study is insignificant.
D000818:Animals; D004247:DNA / Q000235:genetics*; D005796:Genes / Q000187:drug effects*; D006854:Hydrocortisone / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009693:Nucleic Acid Hybridization; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic
D004247:DNA; D006854:Hydrocortisone; D010634:Phenobarbital
Uvelichenie doli povtoriaiushchikhsia posledovatel'nosteĭ DNK v transkriptsionno aktivnykh uchastkakh genoma krysy pri induktsii kortizolom i fenobarbitalom.