Circular RNAs of UDP-Glycosyltransferase (<i>UGT</i>) Genes Expand the Complexity and Diversity of the UGT Transcriptome

The human UDP-glycosyltransferase (UGT) gene superfamily generates 22 canonical transcripts coding for functional enzymes and also produces nearly 150 variant UGT through alternative splicing intergenic splicing. In the present study, our analysis of circRNA databases identified backsplicing events that predicted 85 circRNAs from UGT genes, with 33, 11, 19 UGT1A, UGT2B4, UGT8, respectively. Most these were reported by one database had low abundance in cell- or tissue-specific contexts. Using reverse-transcriptase polymerase chain reaction divergent primers cDNA samples tissues cell lines, we found 13 four genes: UGT1A (three), UGT2B7 (one), UGT2B10 UGT8 (eight). Notably, all eight UGT8 contain open reading frames include start AUG codon encode proteins have common 274–amino acidN-terminal region wild-type protein. We further showed (circ_UGT8-1) was broadly expressed resistant to RNase R digestion, predominately cytoplasm. cloned five into Zinc finger KRAB SCAN domains 1 vector transfected them HEK293T cells. All vectors produced both circRNAsand linear varying circular/linear ratios (0.17–1.14).Western blotting mass spectrometry assays revealed only not translated. conclusion, findings 100 greatly expand complexity diversity transcriptome; however, are at a very level specific cellular contexts, their biologic functions remain be determined. SIGNIFICANCE STATEMENT transcriptome comprises approximately alternatively spliced chimeric transcripts. study thus expanding transcriptome. lines; most tissue- cell-specific therefore biological investigated.