title: Replication of the ampicillin resistance plasmid RSF1030 in extracts of Escherichia coli: separation of the replication cycle into early and late stages.
abstract: The replication cycle of the small resistance plasmid RSF1030 can be divided into two stages with different enzyme requirements: (1) Synthesis of early replicative intermediates containing 7 S DNA catalyzed by DNA polymerase I in the absence of functional dnaZ protein, and (2) replication of early intermediates requiring DNA polymerase III holenzyme (including the dnaZ protein). Early intermediate DNA synthesized in a dnaZ extract can be converted to fully replicated plasmid molecules upon addition to a replication enzyme fraction prepared by ammonium sulfate fractionation of polA I extracts. The first-stage reaction is sensitive to rifampicin, novobiocin, and oxolinic acid, but insensitive to arabinosylcytosine triphosphate (aCTP). Addition of aCTP interferes with the second-stage reaction resulting in the accumulation of late replicative intermediates.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D002474:Cell-Free System; D004256:DNA Polymerase I / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D004261:DNA Replication; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology; D011815:R Factors
chemical_list: D004269:DNA, Bacterial; D000667:Ampicillin; D004256:DNA Polymerase I; D004258:DNA Polymerase III