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.