Drosophila Ecdysone Receptor Study

We used the DamID method to systematically identify the binding sites of Ecdysone Receptor and its heterodimeric partner USP across the whole genome in Drosophila Kc cells. We find that the EcR sites are a subset of the USP sites and that only a proportion are ecdysone regulated from an accompanying ecdysone profiling study. The role of EcR/USP in the ecdysone network appears to be coordinated by the recruitment of many transcription factors as well as signaling molecules. Keywords: DamID, chromatin profiling, DNA microarray In this study we mapped the genomic binding sites of steroid hormone nuclear receptor EcR and USP in Kc167 cells using the DamID method. DamID involves the low level expression of a fusion protein consisting of DNA adenine methyltransferase (Dam) and a chromatin protein of interest. This fusion protein is targeted to the native binding sites of the chromatin protein, where Dam methylates adenines in the surrounding DNA. The methylated DNA fragments were isolated and amplified by selective PCR, labeled with a fluorescent dye and hybridized to whole genome tiling microarrays. In this study,experiments were done with samples obtained from independent experiments and include dye swaps.