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[shimshady]

I have a question, im following the protocol from a paper and the plasmid they have is expressed in bl21 plyse cell line. My question is is i need to clone the plasmid, is it ok to do this in DH5a cell, or do i need a special kind? Thanks

[swanny]

If you're just doing manipulations of the DNA, you can just put the plasmid through DH5. The pLysE plasmid in BL21 is to stop (hopefully) leaky protein expression, typically of toxic proteins. The expression plasmid should have a T7 promoter, so you won't get any expression in DH5, which lacks the gene for T7 RNA polymerase.