Fig. 2

Interaction of rare FOXP2 variants with wild-type FOXP proteins. a–c Bioluminescence resonance energy transfer (BRET) assays for interaction of FOXP2 variants with wild-type (WT) FOXP proteins. HEK293 cells were transfected with YFP-FOXP2 variants (acceptor) and Renilla luciferase (donor) fusions of FOXP2 (a), FOXP1 (b) or FOXP4 (c). The control acceptor protein is a nuclear-targeted YFP. Values are mean corrected BRET ratios ± S.D. (n = 3). Asterisks indicate significant differences compared to wild-type (WT) FOXP2 (p < 0.05, one-way ANOVA followed by Bonferroni post hoc correction). NS not significant. Exact p values for a are <0.0001 for the control and the R553H, R328* and Q390Vfs*7 variants and >0.9999 for all other variants. Exact p values for b are <0.0001 for the control and the R553H, R328* and Q390Vfs*7 variants, 0.024 for the P416T variant, and >0.9999 for all other variants. Exact p values for c are <0.0001 for the control and the R553H, R328* and Q390Vfs*7 variants, 0.088 for the N597H variant, and >0.9999 for all other variants. d Fluorescence micrographs of HEK293 cells transfected with YFP-fusions of the FOXP2 variants p.R553H, p.R328* and p.Q390Vfs*7, together with wild-type FOXP2 fused to mCherry. Nuclei were stained with Hoechst 33342