pZerO vector from INVITROGEN

[Steven Goldberg]

We have been using pZeroI for a couple of months and have had excellent 
results.  I made a partial Sau3A1 library in this vector and nearly 90% 
of the colonies contained inserts of the correct size.  I think the time 
and problems involved screening lots of colonies and/or using CIAP makes 
it very worthwhile to use pZeroI.  It is important to follow their 
instructions about using low salt LB for plating out transformed cells 
and growing colonies in SOB + Zeocin; otherwise, the vector and strains 
transformed with it behave normally.

I've heard that other researchers have used bleomycin from Sigma in 
place of Zeocin (which is simply purified bleomycin). However, I also 
found out from Invitrogen that you can use 25 ug/ml Zeocin to select for 
transformants in E. coli, even though they say to use 50 ug/ml in their 
pZeroI manual, so you can cut down your antibiotic costs considerably 
if it is a problem.