Differential effects of Kid toxin on two modes of replication of lambdoid plasmids suggest that this toxin acts before, but not after, the assembly of the replication complex.
Kid is a small protein that is encoded by plasmid R1. It is a toxin that belongs to a killer system that ensures the stability of the plasmid in host cells. The results of previous studies have suggested that Kid is an inhibitor of DNA replication, possibly acting at the onset of initiation. Here, the authors tested the effects of Kid on orilambda-intitiated and oriJ-initiated replication, which may be driven by both the newly assembled replication complex and the heritable complex. It was found that Kid inhibits only replication that is driven by the newly assembled replication complex. The authors also report that Kid inhibits ColE1-like plasmid replication in vivo, in agreement with the previously reported inhibition of ColE1 during in vitro replication. It is proposed that the Kid toxin acts at the level of replication either by preventing de novo assembly of the replication complex or by impairing the functional interactions of the replication complex at the initiation stage.
Potrykus
Katarzyna
K
Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1.
Santos
Sandra
S
Centro de Investigaciones Biológicas, C.S.I.C., Velázquez 144, 28006 Madrid, Spain2.
Lemonnier
Marc
M
Centro de Investigaciones Biológicas, C.S.I.C., Velázquez 144, 28006 Madrid, Spain2.
Diaz-Orejas
Ramon
R
Centro de Investigaciones Biológicas, C.S.I.C., Velázquez 144, 28006 Madrid, Spain2.
Węgrzyn
Grzegorz
G
Institute of Oceanology, Polish Academy of Sciences, Św. Wojciecha 5, 81-347 Gdynia, Poland3.|Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1.
D001426:Bacterial Proteins / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000494:pharmacology*; D010582:Bacteriophage lambda / Q000235:genetics; D004261:DNA Replication / Q000187:drug effects*; D004269:DNA, Bacterial / Q000096:biosynthesis* / Q000187:drug effects; D008954:Models, Biological; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D018741:Replication Origin
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; C068353:Kid protein, Bacteria