Fig. 1.

CircRNF13 expression is lowly expressed in NPC. A Expression profile of circular RNAs (circRNAs) in 5-8F cells. Five types were included: exon-derived circRNAs, intron-derived circRNAs, anti-sense strand circRNAs, overlapping regions of sense strand circRNAs, and intergenic circRNAs, according to their different looping regions. CircRNF13 was ranked 14th among the top 20, and was screened due to its high abundance (RPM = 0.59). B Expression of circRNF13 was examined in NPC (n = 36) and NPE (n = 12) tissues using RT-PCR, NPE, non-tumor nasopharyngeal epithelial tissues. Data have been represented as mean ± standard deviation (SD). ****, p < 0.0001. C Schematic structure of circRNF13. circRNF13 is 716 bp in length and circularly spliced by 2–8 exons of the RNF13 gene (RefSeq: NM_183383.2) on the chromosome 3q25.1 region, as verified using Sanger sequencing. D circRNF13 is primarily localized in the cytoplasm, as identified using nucleoplasmic separation experiments. U6 was selected as a nuclear marker and GAPDH was selected as a cytoplasmic marker. E Intracellular localization of circRNF13 was examined using fluorescence in situ hybridization. Scale bar: 20 μm. F Stability of circRNF13 and RNF13 mRNA was detected in RNase R-treated HNE2 and CNE2 cells using RT-PCR. Data have been represented as mean ± SD. ****, p < 0.0001