IMPROVEMENT OF hGM-CSF EXPRESSION USING A FUSION SYSTEM BY DIRECTING PROTEIN TO THE PERIPLASMIC SPACE

Bacterial expression systems provide economic and logistic advantages in manufacturing proteins for human therapeutic purposes. However, most such proteins accumulate in insoluble biologically inactive form when overexpressed in bacterial cells. This is the case while attempting to produce recombinant human granulocyte-macrophage colony stimulating factor (hGM-CSF) in E. coli. In this report, different strong promoters are used to compare the yield of expression when the protein is expressed as insoluble and soluble forms. The results obtained indicated that the level of expression was independent of the nature of promoter used. Moreover experimental data presented here suggest that the fusion system which directs hGM-CSF to the periplasmic space not only can prevent inclusion body formation but also improve the level of expression significantly.