Factors that may influence recombinant protein expression - (Sep/30/2005 )
hi,
I have a question: recently I have observed that the expression of the two recombinant protein
were increased when the two recombinant plasmids were co-transfected into the cells. I want to
know why this phenomenon happen. Does it have something to do with the process of
transcription (or post-transcription) or translation (or post-translation)?
If you happen to be familar with it, would you mind sharing with me? Thanks a lot!
I have a question: recently I have observed that the expression of the two recombinant protein
were increased when the two recombinant plasmids were co-transfected into the cells. I want to
know why this phenomenon happen. Does it have something to do with the process of
transcription (or post-transcription) or translation (or post-translation)?
If you happen to be familar with it, would you mind sharing with me? Thanks a lot!
Are you talking about expression in Mammals cells or in E.Coli ?
Pesji
Ya, and what are you expressing (eg transcription factors, ect.)
hi, pesji, what I'm talking about is expression in Mammals cells, named HEK 293T cells.
hi, tap14, what I'm expressing are just two structural proteins. Interaction between them may
exsist from the results,however, I don't know how does the interaction happen, that is, what is
the possible mechanism.
I have no experience with this particular cell line however expression of double transfectants can range form 0% for gene1 and 100% of gene2 to the exact opposite
When you're lucky then you get 50% of each you can feel pretty happy I guess 
The mechanisms are very complex, it also depend very much of the type of promotor you use, are those constructs driven by the same promotor ?
pesji
It is possible that the two promoters are interacting with each other. It is usual during transfection to get concatamerization of DNA and perhaps ligation upon integration of the two DNAs in the genomic DNA of the cells. It is feasible that the enhancers from the two promoters from which you are expressing the proteins may cis-regulate each other causing higher levels of expression.
Interesting hypothesis Tap 14 ! I wonder if it is during integration in the genomic DNA ?
geness are you doing stable expression or ony transient expression with episomal plasmids ?
pesji 
The constructs are driven by the same promotor and the transient expression was done.
Could just be better transfection efficiency.
I don't think so although I have no idea about it.