Biosynthesis of Circular RNA ciRS-7/CDR1as Is Mediated by Mammalian-wide Interspersed Repeats
Biosynthesis of Circular RNA ciRS-7/CDR1as Is Mediated by Mammalian-wide Interspersed Repeats
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DOI：
10.1016/j.isci.2020.101345
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发表时间：
2020-07
期刊：
影响因子：
5.8
通讯作者：
Rei Yoshimoto;K. Rahimi;T. B. Hansen;J. Kjems;A. Mayeda
中科院分区：
文献类型：
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作者：
Rei Yoshimoto;K. Rahimi;T. B. Hansen;J. Kjems;A. Mayeda
环状RNA（CircRNA）是一类具有闭合环状结构的稳定非编码RNA。研究得最好的circRNA之一是ciRS-7（CDR 1as），它作为microRNA miR-7的调节因子;然而，其生物合成途径仍然是一个谜。在这里，我们描述了ciRS-7的生物合成途径。形成circRNA的反向剪接事件通常通过灵长类特异性元件的侧翼反向重复来促进。ciRS-7基因缺乏这些元件，但是，相反，我们确定了一组属于全麦散布重复序列（MIR）家族的侧翼反向元件。HEK 293细胞中的剪接报告基因测定证明，这些反向MIR是通过反向剪接产生ciRS-7所需的，并且CRISPR/Cas9介导的缺失证实了SH-SY 5 Y细胞中内源性MIR元件的需要。使用生物信息学搜索，我们确定了其他几个依赖于MIR-circRNA，并通过实验证实了它们。我们建议使用MIR介导的RNA环化来产生哺乳动物circRNA的子集。
Circular RNAs (circRNAs) are stable non-coding RNAs with a closed circular structure. One of the best studied circRNAs is ciRS-7 (CDR1as), which acts as a regulator of the microRNA miR-7; however, its biosynthetic pathway has remained an enigma. Here we delineate the biosynthetic pathway of ciRS-7. The back-splicing events that form circRNAs are often facilitated by flanking inverted repeats of the primate-specificAluelements. The ciRS-7 gene lacks these elements, but, instead, we identified a set of flanking inverted elements belonging to the mammalian-wide interspersed repeat (MIR) family. Splicing reporter assays in HEK293 cells demonstrated that these inverted MIRs are required to generate ciRS-7 through back-splicing, and CRISPR/Cas9-mediated deletions confirmed the requirement of the endogenous MIR elements in SH-SY5Y cells. Using bioinformatic searches, we identified several other MIR-dependent circRNAs and confirmed them experimentally. We propose that MIR-mediated RNA circularization is used to generate a subset of mammalian circRNAs.