CRISPR-based Live Imaging of Epigenetic Modification-Mediated Genome Reorganization

Epigenetic modifications play an essential role in chromatin architecture and dynamics. The role of epigenetic modification in chromatin organization has been studied by Hi-C from population cells, but imaging techniques to study their correlation and regulation in single living cells are lacking. Here we develop a CRISPR-based EpiGo (Epigenetic perturbation induced Genome organization) system to track epigenetic modification-mediated relocation, interaction or reorganization of genomic regions in living cells. EpiGo-KRAB is sufficient to induce the relocation of genomic loci to HP1 condensates and trigger genomic interactions. EpiGo-KRAB also triggers the induction of H3K9me3 at large genomic regions, which decorate on the surface of HP1 condensates possibly driven by phase separation.