A yeast one-hybrid and microfluidics-based pipeline to map mammalian gene regulatory networks

A combined cross-platform approach is presented to experimentally identify and characterize interactions between mouse transcription factors and regulatory elements at unprecedented resolution and throughput.
We generated a mouse-specific transcription factor (TF) library consisting of 750 full-length sequence-verified open-reading frame clones. We used this resource to develop a cross-platform pipeline to experimentally characterize mammalian regulatory elements of interest for interacting TFs at unprecedented throughput and resolution. Using well-described regulatory elements as well as orphan enhancers, we show that this cross-platform pipeline characterizes known and uncovers novel TF–DNA interactions that are relevant in vivo.
The comprehensive mapping of gene promoters and enhancers has significantly improved our understanding of how the mammalian regulatory genome is organized. An important challenge is to elucidate how these regulatory elements contribute to gene expression by identifying their trans-regulatory inputs. Here, we present the generation of a mouse-specific transcription factor (TF) open-reading frame clone library and its implementation in yeast one-hybrid assays to enable large-scale protein–DNA interaction detection with mouse regulatory elements. Once specific interactions are identified, we then use a microfluidics-based method to validate and precisely map them within the respective DNA sequences. Using well-described regulatory elements as well as orphan enhancers, we show that this cross-platform pipeline characterizes known and uncovers many novel TF–DNA interactions. In addition, we provide evidence that several of these novel interactions are relevant in vivo and aid in elucidating the regulatory architecture of enhancers.