Alleviation of type I restriction in adenine methylase (dam) mutants of Escherichia coli
- Cite this article as:
- Efimova, E.P., Delver, E.P. & Belogurov, A.A. Mol Gen Genet (1988) 214: 313. doi:10.1007/BF00337727
The host-controlled EcoK-restriction of unmodified phage λ.O is alleviated in dam mutants of Escherichia coli by 100- to 300-fold. In addition, the EcoK modification activity is substantially decreased in dam- strains. We show that type I restriction (EcoB, EcoD and EcoK) is detectably alleviated in dam mutants. However, no relief of EcoRI restriction (Type II) occurs in dam- strains and only a slight effect of dam mutation on EcoP1 restriction (Type III) is observed. We interpret the alleviation of the type I restriction in dam- strains to be a consequence of induction of the function which interferes with type I restriction systems.