Enhancer-promoter compatibility is mediated by the promoter-proximal region

Gene promoters induce transcription in response to distal enhancers. How enhancers specifically activate their target promoter while bypassing other promoters remains unclear. Here, we find that the promoter-proximal region is critical for cell-type specific enhancer-promoter compatibility. Using high-throughput genome-engineering in mouse embryonic stem cells (mESC), we systematically replace the endogenous Sox9 promoter with different libraries of core and extended (i.e. full) promoters and assess their response to long-range regulatory elements in mESCs and neural progenitor cells. We find that only a subset of full promoters is activated by distal neuronal enhancers and that the promoter-proximal region is necessary for this enhancer-promoter compatibility. Core promoters alone are insufficient to respond to distal enhancers but modulate the transcriptional output of responsive promoters. Our results suggest that within multipartite regulatory domains, the promoter-proximal region fulfills a facilitator-like function that filters and transmits signal from distal enhancers, ultimaltely conferring enhancer-promoter compatibility.