I've noticed that after transducing my pQCXIP-geneX retrovirus into my cells, I have detectable expression of geneX (by western blot) the following day. Am I just seeing the effects of high expression from only a few cells that had an integration event, or is dsDNA that was reverse transcribed from the viral RNA being transcribed and translated in the absence of integration? A pQCXIP-GFP construct would be useful in answering this question, however I do not have this readily available.
Does anyone have experience with this? I am hoping that retrovirus could be a useful "transient" expression vector that I can use without selection in antibiotics for short-term assays.