大肠杆菌cells used inMAGEexperiments are modified to allow the efficient incorporation of the ssDNAs (oligos) to the bacterial genome.
ThisE. colistrain harbors a plasmid encoding gene for the同源重组蛋白(λ Red system). These proteins are too toxic to be expressed constitutively and therefore, they must be transiently induced.
The genes encoding the homologous recombination protein are under the control of a promoter, which can induce the gene expression in different ways, depending on its type. If the promoter is temperature sensitive, the induction is performed by heat-shock. In the case ofpMA7 plasmid, the promoter is arabinose-inducible. Therefore, to induce the expression of the recombination protein, arabinose should be added to the culture.
MMR stands for mismatched repair. ThisE. colistrain ismutS-deficient, which increases theARF. This strain also lacks the protein that binds to the mismatched position to identify them for repair.