Production and functional characterization of human insulin-like growth factor 1

Abstract

Insulin-like growth factor 1 (IGF-1) is a polypeptide hormone produced mainly by the liver in response to the endocrine growth hormone (GH) stimulus. This protein is involved in a wide range of cellular functions, including cellular differentiation, transformation, apoptosis suppression, migration and cell-cycle progression and other metabolic processes. In the current study, human heart cDNA was employed to isolate IGF-1 encoding fragment using reverse transcriptase (RT) PCR. The isolated fragment was cloned into pET32a expression vector and then transformed into the competent <em>Escherichia coli</em> Origami 2. After selecting the correct colony with the highest expression level, the colony was cultured and induced with IPTG. Recombinant IGF-1 expression was detected by SDS-PAGE and His-tagged protein purification was performed with the affinity chromatography. In order to confirm the activity of the resultant protein, biological activity of the recombinant IGF-1 was assayed through inducing proliferation of MCF-7 cells. Molecular techniques, including PCR, restriction digestion, mass spectrometry analyses, SDS-PAGE and biological activity analyses of this protein confirmed the correct cloning, expression, and function of IGF-1 in this study. Overall, we provided a rapid and cost effective production and purification method for IGF-1 protein, which is biologically active and functional.