Inverse relationship of 3′ UTR GC content and gene expression is reproducible across several experimental modalities and cell types. (A) GC content of 3′ UTR inserts of fast-UTR library transduced BEAS-2B cells FACS-sorted for high or low GFP fluorescence. (B) mRNA half-life of inserts of high or low protein expressing 3′ UTR inserts from A in BEAS-2B cells. (C) Steady-state mRNA abundance of inserts of high or low protein expressing 3′ UTR inserts from A in three human cell lines. For A–C, P-values represent Welch's unequal variance t-test between high and low protein expressing inserts. (D–G) Correlation between 3′ UTR insert GC content and steady-state mRNA abundance (D–F) or mRNA half-life (G) for fast-UTR assays in indicated cell lines. (r) Pearson correlation coefficient, P-value tests null hypothesis that correlation is equal to 0.
