Under the control of CMV promoter in pVAX-1,I have a toxic protein in bacteria that is not possible to express.My insert by itself(without CMV promoter) is not toxic to bacteria but after cloning of it under this promoter,it is impossible to get any colonies or in some cases I have positive colonies but can not get any plasmid after LB broth growth.If I change my vector to an adenoviral one and under the control of CMV promoter, is it possible to have this problem again?
I think you may have a few problems here. The first is that the CMV promoter is usually intended for mammalian expression rather than bacterial expression. I don't know if it works as intended in bacteria.
The second problem is that, if you are getting protein expression, it will be constitutive. Can you move your target sequence to a vector with an inducible promoter?
Lastly, pVAX-1 also contains a T7 promoter. I'm assuming that your bacterial species in E. coli, and while your strain may not permit expression from the T7 promoter, if you are working with a protein expression E. coli strain like BL21(DE3) then you can expect to get expression with a T7 promoter.
So, it's possible that your protein is toxic, but you may have to use a different (and preferably, inducible) expression system to prove it.
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