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Updated: Mar 22, 2026

Use of Alu Element Containing Minigenes to Analyze Circular RNAs
Published on: March 10, 2020
The Biogenesis of Nascent Circular RNAs
Yang Zhang1, Wei Xue2, Xiang Li1
1State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Abstract:
Steady-state circular RNAs (circRNAs) have been mapped to thousands of genomic loci in mammals. We studied circRNA processing using metabolic tagging of nascent RNAs with 4-thiouridine (4sU). Strikingly, the efficiency of circRNA processing from pre-mRNA is extremely low endogenously. Additional studies revealed that back-splicing outcomes correlate with fast RNA Polymerase II elongation rate and are tightly controlled by cis-elements in vivo. Additionally, prolonged 4sU labeling in cells shows that circRNAs are largely processed post-transcriptionally and that circRNAs are stable. Circular RNAs that are abundant at a steady-state level tend to accumulate. This is particularly true in cells, such as neurons, that have slow division rates. This study uncovers features of circRNA biogenesis by investigating the link between nascent circRNA processing and transcription.
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