In Vitro Replication of Rl Miniplasmid DNA
The antibiotic resistance plasmid Rl is composed of a cluster of drug resistance genes (r-determinant) and the resistance transfer factor (RTF). These two segments are flanked by directly repeated IS1 elements (ISla and ISlb). The RTF carries all the genetic information necessary for autonomous plasmid replication and conjugal transfer. The basic replicon of Rl (designated RepA) is situated adjacent to the ISlb element and includes the replication origin oriV and genes involved in replication and copy number control (see Figure 1). Rl replication is controlled by the 90 nucleotide copA RNA and the 11 kdal copB protein which act by inhibiting the expression of the 33 kdal repA protein (1). The repA protein is considered as the limiting factor for the initiation of Rl replication making plasmid DNA synthesis strictly dependent on de novo protein synthesis (2).
KeywordsrepA Protein Conjugal Transfer Plasmid Replication Drug Resistance Gene Oxolinic Acid
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