ABSTRACT
One of the biggest achievements of recombinant DNA technology is the ability to ensure the overproduction of a desired gene product. In this chapter, the authors provide an overview of the general considerations for gene overexpression and some examples. However, the constitutive overproduction of potentially toxic proteins by the elevated gene dosage is usually detrimental to host cell growth. The authors present a method for achieving the high-level expression of the human interleukin-6 (hIL-6) gene as an example of designing for overproduction. On the basis of an analysis of previous attempts to express hIL-6 cDNA, the main strategy the readers employed to increase the production level was improvement of translation efficiency through the installation of dual Shine-Dalgarno sequences and the adoption of a modified nucleotide sequence for encoding hIL-6. Besides gene manipulation to achieve overexpression, both the fementation technology and the downstream processing (including the purification and renaturation of gene products) are also very important.
