Prokaryotic and Mammalian Expression Vectors - Why do they have to be different? (Jun/07/2005 )

I am trying to come up with an explanation why expression vectors for use in bacteria and mammalian cells need to be different? Is it something to do with the promoter? I can't quite seem to formulate it in my head. In other words, can't you use a bacterial expression vector (pGEX etc) to transfect a mammalian cell line (like COS7 or HeLa) to express your gene (for staining etc)? or vice versa?
I hope the question makes sense. Thank you.

s70048

prokaryotic expression vectors cant be used to transform eukaryotic cells.
firstly the prokaryotic vectors ll not replicate in the eukaryotic system bkz they have different origin of replication. secondly the promoter used. bkz the promotor of prokaryotic system mat not function in eukaryotes and vice versa.
i think this is the answer of your question

hi
there is some exception about it. Some vectors are suitable for both utilisation in bacterias and yeast (only yeast unfortunately). the contains ori from bacteria and ampicilin resistance gene (for the bacteria stuff) and replication origin from 2µ and URA3 gene (for yeast stuff).

I don't think there is vectors for both protein expression in bacterias and mammalian cells and i agree with ram2005