Hi,

We have a vector that's got LacZa, driven (as usual) by the Lac promoter, for blue/white screening. We need to change the sequence of the lac promoter (we have another vector, which can't be changed, but has the promoter sequence in it as well, and the homology between the two is causing problems). I can't find any reason why we couldn't simply exchange the Lac promoter for a constitutive one (e.g. the promoter used for bla in a ampR plasmid), but since EVERY lacZa vector I can find uses the lac promoter, I wanted to check there wasn't some underlying reason for this?

Thanks!