Fig 1: SFTA1P is transcriptionally regulated by YAP/TAZ/TEAD in NSCLC cell lines.A A schematic illustration of the lncRNA profiling in MKN28 gastric cancer cells. SFTA1P was identified as a candidate target of YAP/TAZ. Briefly, engineered YAP/TAZ-knockout cells (YKO/TKO) were transduced with empty vector (TKO-EV or TKO) or active form of YAP (TKO-YAP or YOE)/TAZ (YKO-TAZ or TOE). RNA sequencing (n = 2 biologically independent samples) was performed to identify the differentially expressed lncRNAs with the criteria indicated. Venn diagram shows the lncRNAs that were up/downregulated upon overexpression of YAP/TAZ. Bar chart plots the relative expression of SFTA1P using Fragments Per Kilobase of transcript per Million mapped reads (FPKM). The heatmap demonstrates the relative expression of differentially expressed lncRNAs upon YAP/TAZ overexpression. The LOG2 fold-change of each lncRNA upon YAP/TAZ overexpression in two replicates were calculated and plotted. The red arrow pinpoints SFTA1P. B The expression of SFTA1P in lung cell lines was evaluated by RT-qPCR. The relative expression of SFTA1P was calculated by normalizing the SFTA1P expression in the indicated cell lines against that in the BEAS-2B cell line. Mean ± SD, n = 3 (biological replicates). C Western blot analysis of pYAP (S127), YAP, pTAZ (S89), TAZ, CYR61, and GAPDH in the indicated lung cell lines. D–G Knockdown of YAP (D–E), TAZ (D–E), and TEADs (F–G) in H1299 cells. The knockdown efficiencies were evaluated by western blot analysis in (E, G). The RNA expression of SFTA1P, ANKRD1, CTGF, and CYR61 were measured by RT-qPCR following the knockdowns of YAP and TAZ (D) or TEAD1 and TEAD4 (F), Mean ± SD, n = 4 (biological replicates). H The transcriptional activity of the regulatory sequence in the vicinity of SFTA1P TSS was assessed by dual-luciferase assay upon co-transfection of the reporter plasmids and siRNAs against YAP, TAZ, or TEADs in H1299 cells. A schematic illustration of the promoter sequence cloned into a pGL3-Basic vector was shown in the top panel: the 910 bp upstream and 2520 bp downstream sequence of the SFTA1P’s TSS (overlapping with the 1st exon, 1st intron, and the partial sequence of the 2nd exon) was examined. Mean ± SD, n = 3 (biological replicates). I Subcellular localization of SFTA1P was determined by RT-qPCR following subcellular fractionation in H1299 cells. The expression of GAPDH (cytoplasmic marker), U2 snRNA (nuclear marker), and SFTA1P were each quantified and normalized to their corresponding expression levels in the whole-cell lysate. The percentage of the expression in cytoplasmic fraction or nuclear fraction versus the summation of them were calculated and plotted. Mean ± SD, n = 3 (biological replicates). J The presence of Poly(A) tail in SFTA1P transcript was measured by RT-qPCR following reverse transcription using either random hexamer or oligo-dT. The relative expression of each gene was obtained by normalizing against the expression of beta-actin. The comparisons were calculated by normalizing the relative expression in the cDNA library synthesized using random hexamer. Mean ± SD, n = 3 (biological replicates). Statistical significance was determined using Student’s t-test, *p < 0.05, **p < 0.01, ***p < 0.001.