Figure 3. Splicing regulator SRSF1 is required for UPF1_LL expression.

1. Semiquantitative RT–PCR of UPF1_SL or UPF1_LL transcript levels following transfection of HEK‐293 cells with the indicated siRNAs.
2. RT–qPCR analysis of indicated transcripts following transfection of a NT siRNA or SRSF1‐specific siRNA under conditions of CLIP‐UPF1_SL or CLIP‐UPF1_LL overexpression. Relative fold changes are in reference to the GFP‐expressing control line treated with a NT siRNA. Asterisk (*) indicates P < 0.05, as determined by unpaired Student’s t‐test. Black dots represent individual data points and error bars indicate mean ± SD (n = 3 biological replicates). See also Dataset EV3 for P values associated with each statistical comparison.
3. Density plot of changes in relative mRNA abundance as determined by RNA‐seq following SRSF1 overexpression (Data ref: Caputi et al, 2019). Genes were categorized as up‐regulated by siUPF1_total only, siUPF1_LL only, or both siUPF1_total and siUPF1_LL. Statistical significance was determined by K–W test, with Dunn’s correction for multiple comparisons.
4. Density plot as in (C), with genes binned according to enrichment in the CLIP‐UPF1_LL or CLIP‐UPF1_SL affinity purifications.

Source data are available online for this figure.