Expression of recombinant human granulocyte-colony stimulating factor in Escherichia coli using various induction methods

Abstract

Granulocyte-colony stimulating factor (G-CSF) is a glycoprotein that has several therapeutic applications. It consists of 174 amino acids and manufactured by recombinant DNA technology. Until now, the Escherichia coli expression system is still become the first choice for producing recombinant proteins. It is because of this organism is simple to culture in low-cost medium and easy to scale up. In the course to find the most efficient way to produce a high yield of recombinant human G-CSF, we compared several types of medium with different induction methods. In this experiment, recombinant E. coli NiCo21(DE3) harbouring gene encoding rh-GCSF proteins were cultured in various media including auto-induction, non-induction, and IPTG-induction. To determine the protein expression profile, culture sampling was done every 12 h (up to 60 h). Then, the optical density at ʎ 600 nm was measured using UV spectrophotometer and rh-GCSF protein expression were characterized using SDS-PAGE and western blot analyses. ImageJ software was used to calculate the amount of rh-GCSF protein yield using Bovine Serum Albumin (BSA) with known concentration as a standard. Result of this experiment concluded that simple auto-induction medium from Imperial College could produce good amount of rh-GCSF proteins (117 µg/mL) with relatively low production cost and short incubation time.