Figure 6.

CircSOBP promotes IFN-I transcription by regulating TKFC

(A) KEGG enrichment analysis of the downstream pathways of TKFC and its interacting proteins.

(B and C) CircSOBP promoted Poly(I:C) mediated activation of ISRE and IFN promote in a dose-dependent manner. 293T cells were transfected with ISRE or IFN promoter luciferase reporter plasmid, pEGFP-C1-circSOBP expression plasmid or control plasmid and renilla luciferase reporter plasmid, respectively. The RLU values obtained from the renilla luciferase were used for normalization.

(D and E) Western blot showed the effect of circSOBP knockdown or overexpression on Poly(I:C)-mediated activation of RIG-I-like receptor signaling pathway-associated proteins. Using β-actin as a normalization.

(F) CircSOBP disrupted the binding between TKFC-N and MDA5-N. The indicated plasmids were co-transfected in 293T cells and cell lysates were immunoprecipitated with anti-FLAG antibody or control rabbit IgG. Immunoprecipitations were analyzed by western blotting with anti-HA (top) or anti-FLAG (bottom) antibodies. Western blot results of anti-HA and anti-FLAG antibodies in Lysates were used to do normalized to analyze the expression of transfected proteins.

(G and H) Dual luciferase reporter assay showed circSOBP rescued TKFC-N to inhibit MDA5-N-mediated activation of ISRE and IFN promoters in 293T cells.

(I) Expression levels of RIG-I-like receptor signaling pathway-related proteins in U87 and U251 cells treated with TKFC knockdown alone or co-transfected with circSOBP siRNAs.

(J and K) Effect of circSOBP on TKFC-N and TKFC-C to suppress ISRE and IFN promoter activation in 293T cells. The RLU values obtained from the renilla luciferase were used for normalization. All statistics of error bars, S.E.M. from three independent experiments. NS, not significant; ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001; ∗∗∗∗p < 0.0001 by two-tailed Student’s t test.