Fig. 1
From: Functions and mechanisms of circular RNAs in cancer radiotherapy and chemotherapy resistance
Biogenesis, distribution and function of circRNAs. CircRNAs are generated from back splicing of pre-mRNAs in different manners (a, b, c and d). CircRNAs can regulate the activities and functions of DNAs, RNAs and proteins in host cells. In addition, they can be secreted into the extracellular space and transported into adjacent cells or body fluids to regulate cell activities. a. Base pairing-dependent circularization; b. RNA-binding protein (RBP)-dependent circularization; c. Lariat-driven circularization; d. GU-rich and C-rich element-dependent circularization