toxcic genes

[Tim Angelotti]

I am trying to clone a cDNA encoding a extracellular protein.  However, I 
noticed that all of my positive clones (correct orientation) grew very 
slowly and thus gave poor yields.  I am using Bluescript.  I suspect that 
this sequence is toxic, and talking with  a few others working with this 
gene confirmed it may be.  Now the question, what is toxic about it?  Is 
it the sequence of nucleotides, or is it producing some of the protein 
accidently and this is toxic, or is it most likely an alternate open 
reading frame coming from another cryptic promoter?  I have heard all 
three and was wondering if anyone could shed light on this.  If it is any 
of the above, does this mean that any DNA I recover is most likely 
screwed up, rearranged, and would using ABLE or TOPP cells from 
Stratagene help?  

Tim Angelotti
TU Muenchen
Institute for Pharmakologie