Molecular cloning and expression of rat μ-opioid receptor in Escherichia coli (BL21)

The µ (mu) opioid receptors, which mediate the effects of morphine, are widely distributed in brain. The purpose of this study was to design a simple expression system for rat µ-receptor in Escherichia coli (BL21). In this laboratory study, rat µ-receptor cDNA was isolated from pcDNA3 vector using Xba1 and Hind3 restriction enzymes. pET-15b was digested by Nco1 restriction enzyme. µ-receptor cDNA and pET-15b formed a recombinant DNA that was transformed to Escherichia coli (BL21). The insert presence was proved by Rsa1 restriction enzyme and the induction of its expression was performed using IPTG. Finally, the presence of desired insert was confirmed using RSA1, and the colonies that had correct orientation in gene containing plasmid were used for further studies. On the SDS-page gel electrophoresis, a 33 kDa band was observed when IPTG was used at 0.5 and 1 mM concentrations, that is equal to calculated molecular weight of rat µ-receptor. At the end of this project, the expression of rat µ-receptor by IPTG induction was successfully performed.