A mutation that decreases the efficiency of plasmid R1 replication leads to the activation of parD, a killer stability system of the plasmid.
The silent parD (kis/kid) stability operon of plasmid R1 is normally repressed by the co-ordinated action of the Kis and Kid proteins. In this report it is shown that a mutation in repA, the gene of the plasmid replication protein, that reduces two-fold the copy number of the plasmid, leads to the derepression of the parD system. This derepression can be prevented by a suppressor mutation in copB, a copy number control gene of plasmid R1, that increases the efficiency of replication of the repA mutant. Derepression of the wild-type parD system leads to high plasmid stability. These data show the activation of a plasmid stability operon by a mutation that reduces the efficiency of wild-type plasmid replication.
Ruiz-Echevarría
M J
MJ
Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.
de la Torre
M A
MA
Díaz-Orejas
R
R
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011506:Proteins; D015534:Trans-Activators; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C489749:ParD protein, Plasmid R1; D011506:Proteins; D015534:Trans-Activators; C078613:parD protein, Bacteria; C045264:replication initiator protein; D004265:DNA Helicases