Strategies for Gene Expression in Prokaryotic and Eukaryotic System

Abstract

In the recent years, a large number of recombinant or heterologous proteins of human interest have been commercially produced using different prokaryotic and eukaryotic host cells. This is possible due to the rapid development of genetic engineering technologies. Among prokaryotic expression system, Escherichia coli is the most suitable expression host for foreign gene expression and protein production. E. coli is preferred over other bacterial host for gene expression because it has short life, is easier to grow in inexpensive medium, has high cell density, has well-known genetic makeup, and could be genetically manipulated. The major disadvantage of E. coli as a host is that it lacks posttranslational modifications that are required for human proteins. On the other hand, yeasts are excellent host for expression of foreign gene and heterologous protein expression. Yeasts utilize the advantage of unicellular organism because they are easy to genetically manipulate and have the capacity of mRNA splicing and posttranslational modifications for eukaryotic organisms. Among higher eukaryotic organisms, plant cell expression systems are now used as an expression system for vaccines, antigens, and antibodies due to their low production cost. On the other hand, animal or mammalian expression systems are utilized for the synthesis of therapeutic heterologous proteins. The production of proteins utilizing mammalian or animal cell expression system are able to do posttranslational modification, proper protein folding, and product assembly, which are required for biologically functional proteins. The present chapter discusses the strategies of gene expression in prokaryotic and eukaryotic host cell for the recombinant protein expression.