ZFP36 RNA binding site characteristics. (A) Phosphor image of the SDS-PAGE fractionating of the PAR-CLIP immunoprecipitate from doxycycline-induced FLAG/HA-tagged ZFP36 and IGF2BP1 (specificity control) HEK293 cells. (B) Length distribution of ZFP36 mRNA binding sites. (C) Proportion of binding sites mapping to different mRNA regions. (D) ZFP36 site distribution in 3′ UTRs (red line). Median (black), interquartile range (dark blue), interdecile range (light blue) and the outliers (grey lines) are shown for the background. (E) Over-representation of ZFP36 sites (red line) at the distal end of 3′ UTRs relative to the background. (F) Proportion of genes with specific regions of ZFP36 binding sites. nt, nucleotide; PAR-CLIP, photoactivatable ribonucleoside cross-linking and immunoprecipitation; St Dev, standard deviation; UTR, untranslated region; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis.