The SNAG domain of Snail and the SET domain of Suv39H1 are required for their mutual interactions. (a) Flag-tagged Suv39H1 and HA-tagged wild-type or SNAG-deleted Snail were co-expressed in HEK293 cells. After immunoprecipitation, bound Snail or Suv39H1 was examined by western blotting. (b) Schematic diagram showing the functional domains of Snail and sequence alignment of the SNAG domain of Snail with histone H3. The consensus sequence is highlighted in yellow and the critical interacting residues are marked with red cycle on top. (c) WT or mutant Snail was co-expressed with Suv39H1 in HEK293 cells. After immunoprecipitating Suv39H1, bound Snail was examined by western blotting. Input lysates are shown in the bottom panel. (d) Schematic diagram showing the structure of Suv39H1 and the two different deletion constructs used in this study (top panel). HEK293 cells were transiently co-expressed with plasmids encoding Flag-tagged full-length or deletion mutants of Suv39H1 and HA-tagged Snail. Extracts were immunoprecipitated with IgG or specific antibodies against Flag or HA, and bound Suv39H1 or Snail was examined by western blotting. (e) d2-GFP or SNAG-d2-GFP was co-expressed with the catalytic domain of Suv39H1(B) in HEK293 cells. After immunoprecipitation of d2-GFP or Suv39H1, bound Suv39H1 and GFP were examined by western blotting, respectively.