DREF is involved in the steroidogenesis via regulation of shadow gene.

The Drosophila DNA replication-related element-binding factor (dDREF) has been identified as a master regulator of cell proliferation-related genes via its binding to the DRE sequence, 5'-TATCGATA. However, the biological roles of DREF are still to be clarified. Here, we show that DREF mutant females have steroid hormone ecdysone-deficient phenotypes, such as the loss of vitellogenic egg chambers. Furthermore, DREF knockdown in the prothoracic gland of larva prevented pupation and this was rescued via 20-hydroxyecdysone treatment. We found a DRE-like sequence (-625 to -632) in the 5'-flanking region of the Drosophila shadow gene, which catalyzes the conversion of 2-deoxyecdysone to ecdysone, and demonstrated that shadow is a novel target gene of dDREF using quantitative RT-PCR and Chip assays. In addition, we show that the level of dDREF protein correlated with age-related changes in the level of shadow mRNA in the ovaries of wild-type flies. Taken together, our data indicate that dDREF plays a key role in steroid synthesis via regulation of the shadow gene.