Tudor domain mutations impair CB formation and interaction with snRNPs. (A) Alignment of the coilin C-terminal domain aa sequences of the indicated species. The conservation score is reported below the sequences. The mutated aa and deletion are reported as color coded bars in the following figures (yellow K496E, red mutations in the hydrophobic core of the Tudor domain, and brown loop-less mutants). The positions of loop1 and 2 are indicated by bars above the sequences. (B) 3D structure of coilin Tudor domain highlighting the position of the mutations utilized in this study: in yellow K496E, in red mutations in the hydrophobic core of the Tudor domain (I477G, F479G, W554G, and L557G), and in brown deleted loops (Δβ1β2 and Δβ3β4). 3D structure adapted from Shanbhag et al. (2010). (C) Hela^coilinKO and parental HeLa cells transfected with C-terminal mutants tagged with EGFP (left panel; green in merge images). snRNPs were immunolabeled by Y12 antibody (middle panel; magenta in merge images). Insets visualize CBs indicated by arrows magnified three times. Scale bars represent 5 µm for whole-cell images, 1 µm for insets. (D) Immunoprecipitation of EGFP-coilin WT and EGFP-tagged mutants followed by western blotting using Y12 antibody and anti-GFP antibody. Source data are available for this figure: SourceData F5.