Structural models of possible epigenetic editing devices. The structural models of the proteins were taken from PDB repository (zinc finger [PDB:1P47], TALE [PDB:2YPF], CRISPR/Cas9 [PDB:4OO8], M.HhaI [PDB:5MHT], Dnmt3a/3L [PDB:2QRV], TET2 [PDB:4NM6], nucleosome [PDB:1AOI], a 21 amino acid linker was generated in PyMol, and 60 bp DNA sequence was generated with the make-na server (http://structure.usc.edu/make-na/server.html)). The models are drawn to scale and should provide an idea of the architecture of the synthetic constructs used for epigenetic editing. Modelling was done manually in PyMol. Zinc finger, DNA-bound zinc finger array fused to M.HhaI; TALE, synthetic TALE array fused to the catalytic domain of human TET2; CRISPR/Cas9, Cas9 protein fused to a Dnmt3a/Dnmt3L hetero-tetramer. The distances in base pairs and angstroms are indicated.