RADICL-seq identifies general and cell type–specific principles of genome-wide RNA-chromatin interactions
Mammalian genomes encode tens of thousands of noncoding RNAs. Most noncoding transcripts exhibit nuclear localization and several have been shown to play a role in the regulation of gene expression and chromatin remodeling. To investigate the function of such RNAs, methods to massively map the genomic interacting sites of multiple transcripts have been developed; however, these methods have some limitations. Here, we introduce RNA And DNA Interacting Complexes Ligated and sequenced (RADICL-seq), a technology that maps genome-wide RNA–chromatin interactions in intact nuclei. RADICL-seq is a proximity ligation-based methodology that reduces the bias for nascent transcription, while increasing genomic coverage and unique mapping rate efficiency compared with existing methods. RADICL-seq identifies distinct patterns of genome occupancy for different classes of transcripts as well as cell type–specific RNA-chromatin interactions, and highlights the role of transcription in the establishment of chromatin structure. ; This work was funded by a Research Grant from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, to the RIKEN Center for Life Science Technologies (http://www.mext.go.jp/en/). This work was also supported by the Francis Crick Institute, UK, which receives its core funding from Cancer Research UK (FC010110), the UK Medical Research Council (FC010110), and the Wellcome Trust (FC010110). N.M.L. is a Winton Group Leader in recognition of the Winton Charitable Foundation's support towards the establishment of the Francis Crick Institute. N.M.L. isadditionally funded by a Wellcome Trust Joint Investigator Award (103760/Z/14/Z) and the MRC eMedLab Medical Bioinformatics Infrastructure Award (MR/L016311/1). Work in G.C.-B.'s laboratory was supported by the European Union (Horizon 2020 European Research Council Consolidator Grant EPIScOPE), Swedish Research Council (no. 2015-03558), Swedish Brain Foundation (no. FO2017-0075), and Ming Wai Lau Centre for Reparative Medicine, Hong Kong. E.A. was supported by European Union, Horizon 2020, Marie-Skłodowska Curie Actions, grant SOLO no. 794689. Y.A.M. was partially supported by RSF grant 18-14-00240 and the Russian Ministry for Science and Higher Education. Work in V.O.'s laboratory (J.G. and V.O.) was supported by grants from the European Union FP7 (InteGeR Marie Curie Initial Training Network and MODHEP), the Italian Ministry of Education, University and Research MIUR and the National Research Center CNR (Epigen), and grant from KAUST BAS01-01-37. Open access funding provided by Karolinska Institute.