Fig. 4: UCA1 is a sponge RNA for miR-203.

a Cellular fractionation performed in BGC-823 cells followed by RNA isolation and qRT-PCR demonstrates that UCA1 is a cytoplasm-retained lncRNA. β-actin is the cytoplasmic control, and U1 serves as the nuclear control. Error bars indicate S.E.M. Assays were performed in triplicate. b Schematic outline of the predicted binding sites of miR-203 on UCA1 and ZEB2. c, d Relative luciferase activity was performed by dual-luciferase reporter assay. Wild-type (WT) UCA1 cDNA containing putative miR-203 recognition sites or the Mut sequence was cloned in the downstream region of the luciferase gene in the pmirGLO vector. The luciferase-reporter plasmid containing WT or mutant UCA1 was then co-transfected into SGC-7901 and BGC-823 cells along with miR-203 mimics in parallel with Ctrl mimics. Data are expressed as the mean ± SD. Assays were performed in triplicate, **p < 0.01. e SGC-7901 cell lysates were incubated with biotin-labeled lncRNA-UCA1; after pull-down, RNA was extracted and miR-203 was assessed by qRT-PCR. Data are expressed as the mean ± SD. Assays were performed in triplicate, **p < 0.01