Fig. 5.

FMRP interacts with CRMP2 mRNA and negatively regulates CRMP2 translation. A–C qPCR analysis of CRMP2 mRNA levels co-precipitated with FMRP in human HEK293 cells (A), mouse N2a cells (B), and Drosophila S2 cells (C). CRMP2 mRNA levels were normalized to the control C. elegans 18S rRNA and quantified by the relative value of percentage in input. CRMP2 mRNAs display an enrichment in FMRP antibody precipitates compared to the negative control IgG (*P <0.05, unpaired t-test; n = 3 independent experiments). Data are represented as the mean ± SEM. D qRT-PCR quantification analysis of CRMP2 mRNA levels in fractions of sucrose gradients from normal and FXS patient-derived lymphoblastoid cells. The sucrose gradient fractions are divided to three groups: fractions 1–5 mRNP/monosomes, fractions 6–7 light polysomes (L-poly), and fractions 8–11 heavy polysomes (H-poly). CRMP2 mRNAs are increased in the actively translating polyribosomes (H-poly) in FXS cells with a decreased distribution in the mRNP/mono fractions compared with the wild-type (*P <0.05, **P <0.001, unpaired t-test; n = 3 independent experiments). Data are represented as the mean ± SEM.