Are there any issues with tetracycline inducible promoters popping on all of a s - (Feb/10/2014 )

I'm designing a transgene that contains cre recombinase under the control of a tet inducible promoter.  This entire transgene will be flanked by lox P sites.  Therefore, this transgene will negative regulate itself.  I'm just concerned about this promoter getting turned by other factors.  I know tetracycline is found in some FBS, so I will need to use verified tet-free FBS.  Are there any other caveats to this method?

I've found tet inducible promoters to be a bit leaky in mammalian cell culture, so even in the absence of tet you are likely to get a low level expression.

bob1 on Mon Feb 10 21:59:03 2014 said:

I've found tet inducible promoters to be a bit leaky in mammalian cell culture, so even in the absence of tet you are likely to get a low level expression.

I know there are DEX/DOX systems that allow for tighter control.  I wanted to avoid DEX because of off-target effects it may have.  DOX has off target effects too, but I figured my cell cultures are seeing DOX in the media (which contains FBS) anyway.