Extended Data Fig. 7: eIF4G2 binding increases in the 5′ UTRs of dendritic mRNAs upon depolarization and is associated with their increased translation.

a, RBP sites in the 5′ UTRs of mRNAs enriched in resting (rest) and depolarized (dep) dendrites are shown in the heatmap using motifs from RBPmap⁷³. P values were determined using hypergeometric testing. The RBP sites enriched more upon depolarization are shown in the delta (dep minus rest) column. b, The most enriched binding motif of eIF4G2 in 5′ UTRs that are increasingly translated in dendrites upon depolarization by PL-Ribo-seq. eIF4G2 has 4 predicted motifs in RBPmap. c, The distribution of eIF4G2 CLIP peak counts in 3′ UTRs, 5′ UTRs and CDS for all 4 eIF4G2 binding motifs. d, Examples of eIF4G2 target mRNAs identified in resting eIF4G2 CLIP (peak heights, log₂); peaks in similar genomic locations were identified in human cell lines by eCLIP⁸². Pcdh and Pafah1b1 harbor uORFs in their 5′ UTRs. e, The distribution of eIF4G2 CLIP peaks is calculated by combining the eIF4G2 peaks from resting and depolarized primary cortical neurons. f, mRNAs with 5′ UTRs that are increasingly bound by eIF4G2 upon depolarization as determined by eIF4G2 CLIP are referred to as eIF4G2-bound. All detected mRNAs in the differential (depolarized (dep) minus resting (rest)) PL-CLIP (All, n = 17,654) are compared to the eIF4G2-bound group (n = 1,413). g, Differential dendritic CDS translation of all mRNAs with increased ribosomes in their 5′ UTRs (All 5′UTR up, n = 1,920) and differential dendritic CDS translation of mRNAs with increased eIF4G2 binding and increased ribosome occupancy in their 5′ UTRs (5′UTR up + eIF4G2-bound, n = 238) are compared. The latter group is translated more in dendrites upon depolarization compared to the average of all mRNAs with increased ribosome occupancy in their 5′UTRs in dendrites. (f,g) Significance was calculated using the two-sided Kolmogorov-Smirnov test. Box plots show lower and upper hinges corresponding to the first and third quartiles (representing 25th and 75th percentile, respectively). Whiskers extend from the hinge to the 1.5x interquartile range. The center line indicates the median. P values: ns (not significant) >0.05; * <0.05; ** <0.01; *** <0.001; **** <0.0001.