A common set of DNA regulatory elements shapes Drosophila appendages

We mapped open chromatin by FAIRE-seq and measured gene expression by RNA-seq in 3 types of Drosophila samples: staged whole embryos, imaginal discs, pharate appendages. We first demonstrate that regions of open chromatin precisely define regions of enhancer activity in developing embryos. In contrast to the dynamic changes in open chromatin observed between different stages of embryogenesis, we found that the open chromatin profiles in wing, leg, and haltere imaginal discs are nearly identical. This was also true again later in development, where the adult appendages also share nearly identical open chromatin profiles. Therefore, at a given developmental time point, different appendages are specified using a shared set of DNA regulatory elements. However, from one time point to the next, the set of accessible regulatory elements changes. Open chromatin profiles in appendage imaginal discs are almost entirely different than those of the adult appendages. We propose that master regulator transcription factors create morphologically distinct structures by differentially influencing the function of the same set of DNA regulatory modules. Open chromatin profiling during Drosophila development: 3 stages of embryogenesis (2-replicates each); wing, leg, and haltere 3rd instar imaginal discs (3-replicates each); 3rd larval central nervous system (2-replicates); eye-antennal imaginal discs (2-replicates); wing, leg, and haltere pharate appendages (2-replicates each); Genomic DNA Inputs. Sequencing performed on Illumina GAII and HiSeq.