Vapnek D, Spingler E
J Bacteriol. 1974 Dec;120(3):1274-8. doi: 10.1128/jb.120.3.1274-1278.1974.
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.
已使用R质粒DNA（R538 - 1drd）和体内合成的RNA进行了脱氧核糖核酸 - 核糖核酸（DNA - RNA）杂交研究。R质粒DNA从大肠杆菌K - 12中分离出来，互补链在氯化铯 - 聚尿苷酸 - 聚鸟苷酸梯度中分离。用分离出的DNA链和从携带R质粒的细胞中纯化的RNA进行DNA - RNA杂交。结果表明，R质粒DNA在体内发生不对称转录。仅用H链（在氯化铯 - 聚尿苷酸 - 聚鸟苷酸中密度较大的链）检测到杂交。通过在CsCl梯度中测定RNA - DNA杂交体的密度，估计在对数生长的大肠杆菌细胞中，R质粒DNA中超过60%的核苷酸序列被转录。在不携带质粒的大肠杆菌细胞中未检测到R质粒特异性RNA。
