basal expression in bacteria

[ezechiele]

Dear all,
I would like to perform a trans-complementation test in bacteria.
I would like to know in which vector I can clone my cDNA to evaluate if the protein complements the enzyme activity for which bacteria are deficient.
In particular I have to clone also the promoter or does exist a vector with a bacteria promoter which drives a basal expression in my strain?

Help me please

Eze

[canalon]

many vectors come with an inducible promoters. But I guess that if you look well you will find some with strong promoters as well.

Have a look around here for example: http://www.invitrogen.com/content.cfm?pageid=10835

[ezechiele]

Ok thank I am looking at..
My point is if I use a deficient enzymatic strain of bacteria I do not know how induce the expression of my protein.
I am thinking about the TOPO TA vector.... we have lacZ promoter for istance and kanamicyne and ampicillin resistance so it means that thery are expressed. I f I put my cDNa in such a vector does it will be expressed in your opinion?

thanks

[canalon]

in presence of IPTG, yes. But you could select one with a T7 promoter which is strong and constitutive if my memry works correctly.

[ezechiele]

So if T7 is costitutevely expressed in bacteria, so I am ok.... other suggestions?

eze