Dissection of c-AMP Response Element Architecture by Using Genomic and Episomal Massively Parallel Reporter Assays

We designed and assayed synthetic regulatory elements varying c-amp response element number, affinity, distance to the promoter, spacing between multiple CREs, and surrounding sequence content. Using 5 massively-parallel reporter assays, we measured the expression of 17,406 unique sequences when placed upstream of a minimal promoter using next-generation sequencing of barcodes associated with synthesized elements. We then determine how the varied c-amp response element architectures influence expression when these variants are assayed in an episomal and genomic context across a range of forskolin concentrations, an inducer of c-amp response element activity. Included here are all sequences designed and analyzed in the assay. Assay results from certain library designs were not insightful and not included in the main text but are additionally included here in the barcode-mapping and MPRA sequencing datasets. We associated barcodes to variants using next-generation sequencing, then analyzed variant expression using barcode next-generation sequencing on amplified cDNA and DNA samples per assay condition.