Figure 1. circRNAs at a glance.

circRNA can be generated either with the help of reverse complementary repeats or RNA‐binding proteins and exported from the nucleus (1). In the cytoplasm, the circRNA might be bound by multiple factors. These can be RNA‐binding proteins (2), Argonaute proteins loaded with miRNAs as sponge or scaffold (3) or for direct degradation (5), ribosomes (4) or endonucleases that would cause degradation of the circRNA (6). From the non‐degradative binding, the circRNA‐factor complex might diffuse in the cytoplasm or been actively transported in into particular regions of the cell [e.g., the synapse (7)] where it can release its bound cargo or starts to be translated. The enclosure of circRNAs or circRNA factor complexes in vesicle that would be released into the extracellular space would remove circRNAs from the cytoplasm (8). However, protected by the vesicle, the circRNAs or circRNA complexes could reach other cells or tissues and therefore act as messenger molecules or fulfill other unknown functions (9).