Figure 1. Characterization of circPTPRA in BC cell lines. (A) Expression of circPTPRA in normal SV-HUC-1 cells and two BC cell lines (T24 and UM-UC-3). (B) Gel electrophoresis of qRT-PCR products resulting from divergent and convergent primers. GAPDH was used as internal control. (C) Schematic diagram depicting the circPTPRA’s origin from exons 8 and 9 of the PTPRA gene. Sanger sequencing confirmed the back-splicing junction site (blue arrow). (D, E) Analysis of PTPRA mRNA and circPTPRA by qRT-PCR in BC cell lines after actinomycin D treatment. (F) PTPRA mRNA and circPTPRA levels measured by qRT-PCR after RNase R treatment in BC cell lines. (G) Cellular localization of circPTPRA in BC cell lines, as assessed by cytoplasmic and nuclear fractionation assay. (H) FISH assay of indicating the cellular distribution of circPTPRA in UM-UC-3 cells. Scale bar=50μm. Data are presented as mean ± SD. *P < 0.05, **P < 0.01 (Student’s t-test).