Are E.coli strains M15 and pET28a vector systems compatible? Can I over-express my protein which is of plant origin. Previously I was using BL21 DE3 strains. Was confused to use M15 strains for eukaryotic protein expression
Expression from spET vectors requires a strain that carries the T7 polymerase. That is what the DE3 designation in BL21 (DE3) represents, the presence of a lysogenic phage carrying the T7 polymerase gene under control of the lac repressor. The standard M15 strain does NOT have the T7 polymerase so will not express genes cloned into pET vectors. It is however possible to make a derivative of M15 that carries T7, but if you just have the normal M15 then that would not be it.
Expression from spET vectors requires a strain that carries the T7 polymerase. That is what the DE3 designation in BL21 (DE3) represents, the presence of a lysogenic phage carrying the T7 polymerase gene under control of the lac repressor. The standard M15 strain does NOT have the T7 polymerase so will not express genes cloned into pET vectors. It is however possible to make a derivative of M15 that carries T7, but if you just have the normal M15 then that would not be it.
I agree with Michael J. Benedik. The pET (T7 promoter) vectors are most suitable for the BL21 strain. In the pET vector, the target gene is cloned behind the T7 promoter, and the expression is induced by the T7 RNA polymerase provided by the host cell. The pQE (T5 promoter) vectors are most suitable for the M15 strain. Moreover, because your target protein is eukaryotic protein, it is necessary to consider glycosylation of proteins, which bacterial expression systems cannot achieve.
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