title: In vitro system for the replication of the mini R1 factor Rsc11.
abstract: The in vitro synthesis of the mini R1-factor, Rsc11, was achieved using a soluble Escherichia coli cell-extract system. Triton X-100 lysates of the K12 strain 1101 (Rsc11) fractionated by Sephadex G25 chromatography supported the incorporation of labeled deoxyribonucleotides into covalently-closed circular (30S) and open-circular (25S) plasmid DNA as well as other molecules of various sizes. DNA synthesis required the presence of all four ribonucleotides and was rifampicin sensitive. Pulse-chase experiments indicated that this reaction is discontinuous. A dependence on ATP and sensitivity to nalidixic acid suggested this system capable of the replicative synthesis of Rsc11 DNA. Density-shift analysis confirmed this. In addition to hybrid, fully-heavy plasmid supercoils were synthesized indicating that more than one round of replication was completed. Approximately one-third of the molecules available to the system participate in this reaction.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D002474:Cell-Free System; D002499:Centrifugation, Density Gradient; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics; D004270:DNA, Circular / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D011815:R Factors; D013347:Subcellular Fractions
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular; D000667:Ampicillin