title: Asymmetry and extent of in vivo transcripition of R-plasmid deoxyribonucleic acid in Escherichia coli.
abstract: Deoxyribonucleic acid-ribonucleic acid (DNA-RNA) hybridization studies have been performed with R-plasmid DNA (R538-1drd) and in vivo-synthesized RNA. R-plasmid DNA was isolated from Escherichia coli K-12, and the complementary strands were separated in cesium chloride-polyuridylic acid-polyguanylic acid gradients. DNA-RNA hybridization was performed with the separated DNA strands and RNA purified from R-plasmid-carrying cells. The results demonstrated that an asymmetric transcription of the R-plasmid DNA occurs in vivo. Hybridization was only detected with the H strand (denser strand in cesium chloride-polyuridylic acid-polyguanylic acid). By determining the density of the RNA-DNA hybrid in CsCl gradients, it was estimated that greater than 60% of the nucleotide sequences in the R-plasmid DNA are transcribed in logarithmically growing E. coli cells. No R-plasmid-specific RNA was detected in E. coli cells that did not carry the plasmid.
mesh_terms: D001483:Base Sequence; D002250:Carbon Radioisotopes; D002499:Centrifugation, Density Gradient; D004269:DNA, Bacterial / Q000032:analysis; D004270:DNA, Circular / Q000032:analysis; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects*; D005111:Extrachromosomal Inheritance; D009693:Nucleic Acid Hybridization; D012329:RNA, Bacterial; D013936:Thymidine; D013941:Thymine; D014158:Transcription, Genetic; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D004269:DNA, Bacterial; D004270:DNA, Circular; D012329:RNA, Bacterial; D014316:Tritium; D013941:Thymine; D013936:Thymidine