Fig. 7

CircSTX6/PABPC1 complex promotes the stability of SUZ12 mRNA. A qRT-PCR (left) and western blot (right) assays showed the expression of PABPC1 in BCa cells transfected with circSTX6 plasmids. B The efficiency of PABPC1 knockdown or overexpression in EJ cells was verified by qRT-PCR (left) and western blot (right). C qRT-PCR assay showed the expression of circSTX6 in EJ cells transfected with the indicated plasmids. D-E qRT-PCR (D) and western blot (E) assays showed the expression of SUZ12 in EJ cells transfected with the indicated plasmids. F The interaction probabilities of PABPC1 with 3′-UTR of SUZ12 mRNA were predicted by the RNA-Protein interaction prediction (RPISeq) website. Predictions with probabilities > 0.5 were considered “positive”, indicating that the corresponding RNA and protein are likely to interact. G RIP assays showed the association of PABPC1 and SUZ12 (upper). The precipitate was subjected to western blot with the antibodies against PABPC1 (lower). IgG was used as the negative control. H-I RNA stability assays revealed the remaining levels of SUZ12 mRNA in EJ cells transfected with overexpression plasmids of PABPC1 (H) or shRNA specifically targeting PABPC1 (I), respectively. J Luciferase activities of SUZ12 3’UTR were measured after overexpression or knockdown of PBAPC1 in EJ cells, respectively. K Luciferase activities of SUZ12 3’UTR were measured in EJ cells transfected with scramble, sh-PABPC1#1, sh-PABPC1#2, and those co-transfected with vector or circSTX6 plasmid. L Western blot assays showed the expression of SUZ12 in BCa cells transfected with scramble, sh-PABPC1#1, sh-PABPC1#2, and those co-transfected with vector or circSTX6 plasmid. The data are presented as the means ± S.D. of at least three independent experiments. *P < 0.05. P values are calculated by Student’s t test in B, D, G and J and one-way ANOVA in B, D, J and K