Isolation and Characterization of DBR2 Gene Promoter from Iranian Artemisia annua

Artemisia annua is still the only commercial source of Artemisinin. To date, a number of biochemical and molecular studies about Artemisinin's biosynthetic pathway have been carried out. In metabolic engineering approach, isolation and characterization of promoters leads to an understanding of which cis-acting elements are responsible for the regulation of gene expression. DBR2 is a key enzyme in Artemisinin biosynthetic pathway. In order to allow chromosome walking beyond the 5'-flanking region of DBR2, two specific primers were used in combination with 6 arbitrary primers in TAIL-PCR method. A 696bp upstream of DBR2 start codon was isolated and cloned. The subsequent sequence analysis using bioinformatics softwares revealed that there were several cis-acting elements such as TATA-box, CAAT-box, and MeJA-responsive element, and several W-box and light-responsive elements inside the DBR2 promoter. These results can be helpful in understanding of artemisinin biosynthesis regulation and will facilitate metabolic engineering of the compound.