Fig. 6

Aberrant splicing of SKP2 contributes to the reduction of c-Myc ubiquitin. A Graphic illustration of siRNA targeting SKP2-NM_001243120.2. B qPCR analysis of SKP2-NM_001243120.2 expression in ARP1 and CAG cells. C Inhibition of SKP2-NM_001243120.2 prominently decreased cell proliferation in ARP1 and CAG cells detected by MTT. D WB showed that c-Myc expression was decreased in si-SKP2-NM_001243120.2 cells compared with NC cells. E Graphic illustration of SKP2-NM_005983.4-OE and SKP2-NM_001243120.2-OE plasmids linked with HA and FLAG tag, respectively. F SKP2-NM_001243120.2 FLAG-tagged isoform upregulated c-Myc expression while the SKP2-NM_005983.4 HA-tagged isoform downregulated c-Myc expression in ARP1 and CAG cells. G WB confirmed that c-Myc expression was increased in circHNRNPU_603aa-OE cells and downregulated in si-circHNRNPU_603aa cells. H Co-IP experiment indicated an interaction between SKP2 and c-Myc in MM cells. I SKP2-NM_001243120.2 FLAG-tagged isoform or SKP2-NM_005983.4 HA-tagged isoform overexpressed cells were treated with MG132 for 12 h. An ubiquitination assay was performed using anti-c-Myc magnetic beads, and the ubiquitylated proteins were detected by Ub antibody. The data are presented as mean ± SD.*p < 0.05, **p < 0.01, ***p < 0.001