Fig. S5.

(A) Schematic of the vectors used for immunofluorescence studies. Fmr1 mRNA harboring the reference 3′UTR or the 746C variant allele, in which four box B sequences were inserted, was visualized in primary hippocampal neurons by tagging it with mCherry fused to λN22 protein that binds to box B sequences, as previously described (61). (B) Fmr1 mRNA with a control 3′UTR colocalizes and is trafficked with FMRP. (Scale bar, 5 µm.) (C) Fmr1 with the 746C variant allele included in the 3′UTR colocalizes and is trafficked with FMRP. (Scale bar, 5 µm.) Empty arrowheads indicate FMRP/Fmr1 mRNA granules that are immobile. White arrowheads indicate dynamic FMRP/Fmr1 mRNA granules.