fig2

Figure 2. The functions of circRNAs. (A) Nuclear-localized EcircRNAs can interact with promoters to regulate transcription by recruiting transcriptional regulatory proteins to promoter regions; (B) miRNA sponge. CircRNAs with multiple miRNA binding sites can act as competing endogenous RNAs, thereby modulating the accessibility of miRNAs on mRNAs; (C) Translatable circRNAs. Cytoplasmic circRNAs with m⁶A sites or IRESs are potentially translated through different mechanisms; (D) Protein sponge. Some circRNAs bind to proteins such as ribonucleoproteins and RBPs and are involved in epigenetic regulation; (E) Direct interaction with mRNAs. RBP: RNA-binding protein; m⁶A: N⁶-methyladenosine modification; IRESs: internal ribosome entry sites.