Optimizing expression of recombinant jasmonate ZIM-domain protein from Salvia miltiorrhiza

OBJECTIVE: Accumulation of tanshinton in Salvia miltiorrhiza are enhanced by exogenous application of jasmonates. The core JA signaling module COI1/JAZ/MYC2 play a central role on control of downstream gene expression in the JA pathway. To obtained the antibody of SmJAZ, SmJAZ recombinant protein was expressed in Escherichia coli and optimal expression was performed. METHOD: The full-length SmJAZ1 ORF was sub-cloned in a prokaryotic expression vector pET32a. The recombinant fusion protein had high expression level in BL21 (DE3) strain of E. coli, and SDS-PAGE analysis showed its molecular weight was about 24 kDa. RESULT: The induction of E. coli [pET32-JAZ1] in different temperature, induction time, IPTG concentrations and IPTG adding time of E. coli were performed. The induction time and the induction temperature are positively related trends with SmJAZ1 protein expression, and IPTG concentration had no significant impact in protein expression, whereas IPTG adding time had significant impact on protein expression. CONCLUSION: Shaking the culture at 30 degrees C until the A600 is approximately 0.9 (2 h in LB), and add IPTG to a final concentration of 0.1 mmol x L(-1), and then the optimal expression of SmJAZ1 recombinant protein were accumulated after the induction time of 20 h.