Cloning and expression analysis of 2-oxoglutarate-dependent dioxygenase from Schisandra chinensis

The 2-oxoglutarate-dependent dioxygenase (2-ODD) gene is regarded as the key enzyme gene involved with aryl naphthalene lignan-podophyllotoxin synthesis. To study the expression pattern and function of the Sc2-ODD gene, a full-length cDNA of the gene was cloned. Bioinformatic analysis, the expression pattern, and prokaryotic expression and purification were implemented. The open reading frame of Sc2-ODD gene was 1 077 bp and encoded 358 amino acids with a molecular weight of 40.16 kD. The Sc2-ODD protein contained the conserved 2OG-FeII-oxy sequence of the 2-ODD protein. The results of phylogenetic analysis revealed that Sc2-ODD is most closely related to Corchorus olitorius 2-ODD. qRT-PCR results showed that Sc2-ODD expression displayed obvious up-regulation at the fruit-swelling stage, then down-regulation in the fruit-coloring period. The Sc2-ODD gene was cloned into the bacterial expression vector pGS21T, the recombinant Sc2-ODD protein was expressed in Escherichia coli Rosetta (DE3) cells and the fusion protein was obtained and purified by GST fusion protein purification technology. This study will lay a foundation for further research on the function and expressional regulation of the Sc2-ODD gene in the aryl naphthalene lignans biosynthesis pathway, and also provides a scientific basis for improving the lignan content and the medicinal quality of Schisandra chinensis using plant genetic engineering.