title: Coupling between the basic replicon and the Kis-Kid maintenance system of plasmid R1: modulation by Kis antitoxin levels and involvement in control of plasmid replication.
abstract: kis-kid, the auxiliary maintenance system of plasmid R1 and copB, the auxiliary copy number control gene of this plasmid, contribute to increase plasmid replication efficiency in cells with lower than average copy number. It is thought that Kis antitoxin levels decrease in these cells and that this acts as the switch that activates the Kid toxin; activated Kid toxin reduces copB-mRNA levels and this increases RepA levels that increases plasmid copy number. In support of this model we now report that: (i) the Kis antitoxin levels do decrease in cells containing a mini-R1 plasmid carrying a repA mutation that reduces plasmid copy number; (ii) kid-dependent replication rescue is abolished in cells in which the Kis antitoxin levels or the CopB levels are increased. Unexpectedly we found that this coordination significantly increases both the copy number of the repA mutant and of the wt mini-R1 plasmid. This indicates that the coordination between plasmid replication functions and kis-kid system contributes significantly to control plasmid R1 replication.
authors: Department of Molecular Microbiology and Infection Biology, C/ Ramiro de Maéztu 9, Centro de Investigaciones Biológicas-CSIC, 28040 Madrid, Spain. villarejo@cib.csic.es.
authors: Juan
authors: J
authors: López-Villarejo
authors: Department of Molecular Microbiology and Infection Biology, C/ Ramiro de Maéztu 9, Centro de Investigaciones Biológicas-CSIC, 28040 Madrid, Spain. dami_lm@cib.csic.es.
authors: Damián
authors: D
authors: Lobato-Márquez
authors: Department of Molecular Microbiology and Infection Biology, C/ Ramiro de Maéztu 9, Centro de Investigaciones Biológicas-CSIC, 28040 Madrid, Spain. ramondiaz@cib.csic.es.
authors: Ramón
authors: R
authors: Díaz-Orejas
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D056915:DNA Copy Number Variations; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008957:Models, Genetic; D009154:Mutation; D011815:R Factors / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018741:Replication Origin; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004268:DNA-Binding Proteins; C068353:Kid protein, Bacteria; C068354:Kis protein, Bacteria; C489749:ParD protein, Plasmid R1; D012333:RNA, Messenger; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases