DONSON and glioma: It has been reported that circ-DONSON, which is mainly distributed in the nucleus, regulates the transcription of SOX4 by recruiting the NURF complex to its promoter 43, and circ-FBXW7, which is also located in the nucleus, represses glioma tumorigenesis through encoding a novel 21-kDa protein, FBXW7-185aa 44.