ExoIN

For our recently developed ExoIN system we made use of a protein fusion approach and designed a eukaryotic expression construct encoding a fusion protein consisting of an engineered puromycin N-acetyltransferase (briefly, PuroR) fused to the N terminus of the ExoIN-tag, which in turn is fused to the N terminus of a protein of interest (see further information).

The obvious advantage of this expression construct is that any cell that is resistant to puromycin expresses by definition the protein of interest, since PuroR and the protein of interest are not only expressed from the same transcript but moreover, are expressed as a polyprotein that is efficiently processed to the respective free proteins by endogenous proteases in virtually every eukaryotic cell.

With ExoIN, we provide our customers an expression system that allows easy and highly efficient selection of mammalian cells ectopically expressing a protein of interest. This system allows for rapid and reliable generation of homogenous populations of cells, readily usable as protein production or assay cell line.

By applying that system, we are able to generate such homogenous cell lines within a fortnight and reduce the time consumption for the generation of stable clones by at least 50 % compared to other available expression systems. Moreover, the ExoIN system enables us to generate stable homogenous populations of cells with different expression levels simply by applying different strength of selection pressure.

ExoIN is combinable with EndoOUT in order to study mutant protein function in a “null” background.

Further information