Heterologous expression and purification of porcine fat mass and obesity-associated gene in Escherichia coli

A porcine fat mass and obesity-associated gene (pFTO) was cloned into the expression vector pET30a(+) and heterologously expressed in Escherichia coli. The effects of isopropyl β-D-thiogalactopyranoside (IPTG) concentration and induction time on the expression of recombinant pFTO were assessed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the molecular mass of the recombinant pFTO protein was about 56 kDa, and the recombinant protein could be induced efficiently in E. coli BL21 by the addition of 0.75 mM IPTG for 4 h at 30 °C. The recombinant pFTO fusion protein was purified using Ni-IDA affinity chromatography with a yield of about 1.8 μg/mL protein. The protein was further confirmed by western blot analysis. An in vitro biological activity assay demonstrated that the refolded purified 2 μg/mL recombinant pFTO protein increased 3T3-L1 preadipocyte proliferation. The present work should be useful for the production of sufficiently large amounts of recombinant pFTO protein for further functional analysis.