Cheng Huang, Jaber Firas, Partha Pratim Das, Yu Bo Yang Sun, Anja S Knaupp, Joseph Chen, Melissa L. Holmes, Christian M. Nefzger, Fernando J. Rossello, Pratibha Tripathi, Trung V. Nguyen, Ralf B. Schittenhelm, Sue Mei Lim, Kayla Wong, Xiaodong Liu, Monika Mohenska, Jody J. Haigh, Jan Schröder, Ryan Lister, Jahnvi Pflueger, Kathryn C. Davidson, Ethan Ford, Jose M. Polo, and Michael R. Larcombe
Summary Cellular identity is ultimately dictated by the interaction of transcription factors with regulatory elements (REs) to control gene expression. Advances in epigenome profiling techniques have significantly increased our understanding of cell-specific utilization of REs. However, it remains difficult to dissect the majority of factors that interact with these REs due to the lack of appropriate techniques. Therefore, we developed TINC: TALE-mediated isolation of nuclear chromatin. Using this new method, we interrogated the protein complex formed at the Nanog promoter in embryonic stem cells (ESCs) and identified many known and previously unknown interactors, including RCOR2. Further interrogation of the role of RCOR2 in ESCs revealed its involvement in the repression of lineage genes and the fine-tuning of pluripotency genes. Consequently, using the Nanog promoter as a paradigm, we demonstrated the power of TINC to provide insight into the molecular makeup of specific transcriptional complexes at individual REs as well as into cellular identity control in general., Graphical Abstract, Highlights • TINC allows the isolation of a specific locus for molecular analyses • TINC identified hundreds of proteins at the Nanog promoter • RCOR2 is a component of the pluripotency network in embryonic stem cells • RCOR2 is required for efficient differentiation, Here, Knaupp and colleagues describe TINC, an epigenetic method that allows interrogation of mammalian regulatory complexes at a single-locus resolution. TINC was applied to dissect the transcriptional complex at the Nanog promoter in embryonic stem cells, revealing hundreds of interactors, including RCOR2, hence redefining how this gene is regulated in pluripotency.