Fig 1: The SRSF3 protein and the NEXT complex associated with the RNA exosome are functionally connected to degrade intronless mRNAs. (a) Western blot analysis showing protein depletion upon the indicated siRNA treatments. Anti-Tubulin antibody was used as a loading control. * Indicates non-specific bands. (b) mRNA stabilization by exosome depletion: RT-qPCR analysis of nuclear RNAs from HeLa cells transfected with the indicated siRNAs together with the Renilla luciferase and BDLF1 intronless constructs. proEXT1 PROMPT served as a positive control. Data are displayed as mean values normalized to the control siRNA and GAPDH mRNA as an internal control. Error bars represent the s.d. from three independent experiments (n = 3). (c) Western blotting analysis showing the overexpression of the Flag tagged-hMTR4 protein and depletion of the SRSF3 protein after siRNA treatment. Anti-Tubulin antibody was used as a loading control. (d) RT-qPCR analysis of nuclear RNAs from HeLa cells transfected with the indicated siRNAs together with the Renilla luciferase and BDLF1 intronless constructs. Data are displayed as mean values normalized to the control siRNA and GAPDH mRNA as an internal control. Error bars represent the s.d. from three independent experiments (n = 3). (e) Western blotting analysis showing expression of the NEXT components RBM7, ZCCHC8 and hMTR4 in HeLa cells transfected with either a control siRNA (lane 1), or a siRNA specific for SRSF1 (lane 2), SRSF3 (lane 3) or SRSF7 (lane 4). Anti-Tubulin antibody was used as a loading control. *Indicates non-specific bands.