Circular RNAs (circRNAs) belong to a diverse class of stable RNAs expressed in all cell types. Their proposed functions include sponging of microRNAs (miRNAs), sequestration and trafficking of proteins, assembly of multimeric complexes, production of peptides, and regulation of transcription. Backsplicing due to RNA structures formed by an exceptionally high number of Alu repeats lead to the production of a vast repertoire of circRNAs by human Survival Motor Neuron genes, SMN1 and SMN2, that code for SMN, an essential multifunctional protein. Low levels of SMN due to deletion or mutation of SMN1 result in spinal muscular atrophy (SMA), a major genetic disease of infants and children. Mild SMA is also recorded in adult population, expanding the spectrum of the disease. Here we review SMN circRNAs with respect to their biogenesis, sequence features, and potential functions. We also discuss how SMN circRNAs could be exploited for diagnostic and therapeutic purposes.

环状 RNA (circRNA) 属于在所有细胞类型中表达的多种稳定 RNA。它们提出的功能包括 microRNA (miRNA) 的海绵作用、蛋白质的隔离和运输、多聚体复合物的组装、肽的产生以及转录的调节。由于大量 Alu 重复形成的 RNA 结构引起的反向剪接导致人类运动神经元生存基因SMN1和SMN2产生大量的 circRNA ，这些基因编码 SMN（一种重要的多功能蛋白）。由于SMN1缺失或突变导致 SMN 水平低，导致脊髓性肌萎缩症 (SMA)，这是婴儿和儿童的一种主要遗传病。成年人中也有轻度 SMA，扩大了该疾病的范围。在这里，我们回顾SMN circRNA 的生物发生、序列特征和潜在功能。我们还讨论了如何利用SMN circRNA 进行诊断和治疗。