Department of Biochemistry, McGill University, Montreal, Canada, H3G 1Y6.
Department of Oncology, McGill University, Montreal, Canada, H3A 1G5.
RNA. 2021 Jun;27(6):676-682. doi: 10.1261/rna.078261.120. Epub 2021 Mar 24.
Circular (circ) RNA expression vectors are used as a method of identifying and characterizing RNA sequences that harbor internal ribosome entry site (IRES) activity. During the course of developing a vector series tailored for IRES discovery, we found evidence for the occurrence of -spliced mRNAs arising when sequences with promoter activity were embedded between the upstream CTD and downstream NTD exons of the pre-mRNA. These -spliced products regenerate the same open reading frame expected from a circRNA and can lead to false-positive signals in screens relying on circRNA expression vectors for IRES discovery. Our results caution against interpretations of IRES activity solely based on results obtained from circRNA expression vectors.
环形 (circ) RNA 表达载体被用作鉴定和表征具有内部核糖体进入位点 (IRES) 活性的 RNA 序列的方法。在开发专门用于 IRES 发现的载体系列的过程中，我们发现了证据，证明当具有启动子活性的序列嵌入 pre-mRNA 的上游 CTD 和下游 NTD 外显子之间时，会出现 -剪接的 mRNAs。这些 -剪接产物从一个 circRNA 中重新产生相同的开放阅读框，并可能导致基于 circRNA 表达载体进行 IRES 发现的筛选中出现假阳性信号。我们的结果告诫人们不要仅仅根据 circRNA 表达载体获得的结果来解释 IRES 活性。
