NET-prism enables RNA polymerase-dedicated transcriptional interrogation at nucleotide resolution

The advent of quantitative approaches that enable interrogation of transcription at single nucleotide resolution has allowed a novel understanding of transcriptional regulation previously undefined. To better map transcription genome-wide at base pair resolution and with transcription/elongation factor dependency we developed an adapted NET-seq protocol called NET-prism (Native Elongating Transcription by Polymerase-Regulated Immunoprecipitants in the Mammalian genome). NET-prism introduces an immunoprecipitation to capture RNA Pol II – associated proteins, which reveals the interaction of these proteins with active RNA Pol II. Application of NET-prism on different Pol II variants (Pol II S2ph, Pol II S5ph), elongation factors (Spt6, Ssrp1), splicing factors (Sf1), and components of the pre-initiation complex (PIC) (TFIID, and Mediator) reveals diverse Pol II signals, at a single nucleotide resolution, with regards to directionality and intensity over promoters, splice sites, and enhancers/super-enhancers. NET-prism will be broadly applicable as it exposes transcription factor/Pol II dependent topographic specificity and thus, a new degree of regulatory complexity. Overall design: NET-prism profiles were generated for Pol II S2ph, Pol II S5ph, Spt6, Ssrp1, Sf1, TFIID, and Mediator