Fig. 2: Mechanisms of circRNA functions.
From: CircRNAs in colorectal cancer: potential biomarkers and therapeutic targets
A CircRNAs can act as sponges or decoys for miRNAs. MiRNA binding to circRNAs may release target mRNAs from miRNA-dependent degradation, resulting in more effective translation. B circRNAs containing RBP motifs (such as HuR, EIF4A3, P21, and CDK2) may act either as sponges or decoys for the aforementioned proteins while regulating their functions. C circRNAs may interact with the RNA polymerase II (Pol II) complex containing the U1 snRNP in the promoter region of targeted genes, and significantly enhance its function. D circRNAs contain ribosome entry sites that may be translated to produce unique peptides under specific conditions.
