CUIC Motif Is Involved with Alternative 5′ End and Netrin-1-Stimulated Translation of Axonal RP mRNAs
(A) Plot showing the difference of the position of 5′ terminal of CUIC-containing mRNAs between the axon and the whole embryo. The x axis indicates the relative position of 5′ terminal compared to CUIC.
(B) Diagram showing 2 isoforms of the CUIC-containing mRNA with alternative 5′ ends and the 5′ TOP mRNA.
(C) Diagram (left), gel image (middle), and Sanger sequencing result (right) of 5′ RACE products of Rps4x/eS4 mRNAs in axon and eye samples.
(D and E) Representative images (D) and quantification of quantitative immunofluorescence (QIF) (E) for Rps14/uS11 (n = 42, control; 59, CHX; 66, Netrin-1; 64, Netrin-1 + CHX) and Rps4x/eS4 (n = 59, control; 50, CHX; 70, Netrin-1; 44, Netrin-1 + CHX) in RGC growth cones with or without Netrin-1 (5 min)/cycloheximide (CHX) treatment (bars, average with 95% confidence interval [CI], Mann-Whitney U test compared to the control, ∗∗∗p ≤ 0.001, ∗p ≤ 0.05). Scale bar, 5 μm.
(F and G) Plots (F) and representative images (G) of relative fluorescence recovery of Venus reporter constructs after photobleaching (error bar, SEM) in RGC growth cones. ∗∗∗p < 0.0001; 2-way ANOVA comparing full-length UTRs (n = 8) with Del-motif (n = 12). Scale bar, 2 μm.
(H) Moving average (20 s window) of the count of detected translation events per unit area per second with the Netrin-1 stimulation in single-molecule translation imaging. p value: Mann-Whitney U test between full-length UTRs (n = 11) and Del-motif (n = 12) using the total count in each growth cone.