Alleviation of type I restriction in adenine methylase (dam) mutants of Escherichia coli.
The host-controlled EcoK-restriction of unmodified phage lambda.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.
Efimova
E P
EP
Institute of Experimental Cardiology, National Cardiology Research Center, USSR Academy of Medical Sciences, Moscow.
Delver
E P
EP
Belogurov
A A
AA
D010582:Bacteriophage lambda / Q000235:genetics*; D015253:Deoxyribonucleases, Type I Site-Specific / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D008780:Methyltransferases / Q000235:genetics*; D009154:Mutation; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)
D029968:Escherichia coli Proteins; D008780:Methyltransferases; C058693:Dam methyltransferase; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C499294:dam protein, E coli; C029602:endodeoxyribonuclease EcoK; D015253:Deoxyribonucleases, Type I Site-Specific