Some RM systems (restriction-modification systems) are plasmid-borne and are transferred through bacterial conjugation. As you all know, there are two genes in an RM system, the gene that codes for the restriction enzyme that restricts a certain nucleotide sequence and the other that codes for the methyltransferase that methylate the sequence to protect the cell from its own restriction enzymes. If these genes are both being expressed at the same rate after the bacteria receives this plasmid, how is the bacteria's DNA protected from the restriction enzymes for the first few hours of expression if the methyltransferase have not yet methylated the entire host genome yet?
Thank you,
CDB