Fig. 4From: Long noncoding RNA SGO1-AS1 inactivates TGFβ signaling by facilitating TGFB1/2 mRNA decay and inhibits gastric carcinoma metastasisSGO1-AS1 promotes TGFB1/2 mRNA decay by interacting with PTBP1. a. PTBP1-knockout (KO) MKN28 cells were produced using the CRISPR/Cas9 system. Disruption of the PTBP1 locus. b. Volcano plots showing the differentially expressed genes in the PTBP1-KO vs. control cells. c. KEGG analysis of the downregulated genes in the PTBP1-KO vs. control cells. d-e. qRT-PCR and Western blot analysis were used to validate the expression of genes involved in the TGFβ pathway in the indicated cells. f. GSEA results plotted to illustrate the correlation between the expression of SGO1-AS1 and TGFβ target genes in the TCGA stomach adenocarcinoma RNA-seq dataset. g. Overlay of differentially expressed genes following the PTBP1 knockout and PTBP1-binding target mRNAs. h. PTBP1 RIP assay was performed to analyze the interactions between the PTBP1 protein and TGFB1/2 or ID2 mRNA in MKN28 cells. The relative fold enrichment of these mRNAs compared to IgG was determined by qRT-PCR. SMAD5 and GAPDH served as negative controls. i-j. The enrichment of SGO1-AS1 RNA and TGFB1/2 mRNA in PTBP1 immunoprecipitants was detected by a RIP-qPCR assay in SGC7901 cells with SGO1-AS1 overexpression (i) and MKN28 cells with SGO1-AS1 knockdown (j), respectively. k-l. TGFB1/2 mRNA stability assessment in the indicated cells treated with actinomycin D (5 μg/mL) for 2, 4, 8 and 16 h. TGFB1/2 mRNA abundance relative to GAPDH quantified by qRT-PCR (n = 3 independent experiments). m. Western blotting analysis of the TGFβ1/2 and PTBP1 protein levels in the indicated cells. n. TGFB1/2 mRNA stability assessment in control and PTBP1-KO MKN28 cells transfected with siAGO2 or control siRNA. Error bars represent SDs. *P < 0.05, **P < 0.01, ***P < 0.001Back to article page