Figure 5.

NSUN2 regulates nuclear-cytoplasmic shuttling and RNA-binding ability of ALYREF. (A) Immunofluorescence staining of ALYREF (red color) and ASF (green color) upon NSUN2 knockdown (top); line scan graphs (middle) and peak density quantification of line scan graphs (bottom) for ALYREF are also shown. Scale bar, 10 μm. Error bars indicate SEM (n = 120). (B) Western blotting (left) and quantification (right) of nuclear and cytoplasmic distribution of ALYREF in control and NSUN2-knockdown HeLa cells. The protein loading for the cytoplasmic fraction is about 2.5-fold higher than that for the nuclear fraction. PARP1 and TUBULIN serve as nuclear and cytoplasmic markers, respectively. Error bars indicate SEM (n = 3). (C) Immunofluorescence staining of ALYREF (red color) in NSUN2-knockdown HeLa cells transfected with control EGFP (EGFP-EV), EGFP-tagged siNSUN2-insensitive wild-type NSUN2 (EGFP-WT-Ins) or mutant (EGFP-DM-Ins) plasmids (top); line scan graphs (middle) and peak density quantification of line scan graphs (bottom) for ALYREF are also shown. Scale bar, 10 μm. Error bars indicate SEM (n = 120). (D) Western blotting (top) and quantification (bottom) of nuclear and cytoplasmic distribution of ALYREF in NSUN2-knockdown HeLa cells transfected with empty Myc expression vector (Myc-EV), Myc-tagged siNSUN2-insensitive wild-type NSUN2 (Myc-WT-Ins), or Mutant (Myc-DM-Ins). The protein loading for the cytoplasmic fraction is about 2.5-fold higher than that for the nuclear fraction. PARP1 and TUBULIN serve as nuclear and cytoplasmic markers, respectively. Error bars indicate SEM (n = 3). (E) PAR-CLIP assay (left) and quantification (right) of RNA pulled down by Flag-ALYREF upon NSUN2 knockdown. RNA labeled with biotin at 3′ end of RNA (End Biotinylation Kit, Thermo) was visualized by the chemiluminescent nucleic acid detection module. m⁵C-modified RNAs were visualized by dot blotting using m⁵C antibody. Error bars indicate SEM (n = 3). (F) Rescue PAR-CLIP assay (left) and quantification (right) of RNA pulled down by Flag-ALYREF in NSUN2-knockdown HeLa cells transfected with Myc-EV, Myc-WT-Ins, or Myc-DM-Ins. RNA labeled with biotin at 3′ end of RNA (End Biotinylation Kit, Thermo) was visualized by the Chemiluminescent nucleic acid detection module. Error bars indicate SEM (n = 3). P values were calculated by Student's t-test.