环状RNA
环状RNA（Circular RNA，简称circRNA）为生物细胞中的一类RNA，由线状RNA5'端与3'端经共价结合（反向剪接）而形成[1]。有些环状RNA可编码蛋白质[2][3]，有些则为非编码RNA，大多数环状RNA的功能均仍未知，过去认为环状RNA仅是RNA剪接过程中产生的副产物，在细胞中数量不多且序列保守性低，应不具重要功能[4]，但近年许多研究已渐推翻此观点[1][5][6]。环状RNA因不具5'端或3'端，不会被外切酶切割，在细胞中应较多数的线状RNA稳定[6]。
目前人类细胞中已有超过25,000种环状RNA被发现[7]，多位于细胞质中[6]，也有些源于基因内含子的环状RNA（环状内含子RNA，简称ciRNA）会留在细胞核中调控自身基因的表现[8]。有些环状RNA可能可作为“miRNA海绵”（miRNA sponge）与miRNA结合，使后者无法和目标mRNA结合而阻断RNA干扰[9][10]。环状RNA还可能与一些RNA结合蛋白结合[5]、由内部核糖体进入位点（IRES）启动转译而编码蛋白质[11]、在细胞中运输与储存miRNA等[12]。环状RNA的调控异常可能与多种癌症和神经退化性疾病有关[13][14]。
除真核生物经反向剪接形成的环状RNA外，生物还有数种其他生成环状RNA的机制，例如第二型内含子剪接的产物、某些藻类与古菌生成tRNA过程的中间产物等[7]，另外D型肝炎与类病毒的基因组也是环状RNA[15]。
参考文献
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- ^ 1.0 1.1 Salzman, J; Gawad, C.; Wang, P.L.; Lacayo, N; Brown, PO. Circular RNAs are the Predominant Transcript Isoform from Hundreds of Human Genes in Diverse Cell Types. PLOS ONE. 2012, 7 (2): e30733. Bibcode:2012PLoSO...730733S. PMC 3270023
. PMID 22319583. doi:10.1371/journal.pone.0030733.
- ^ New study shows circular RNA can encode for proteins. Science Daily. 2017 [3 May 2018]. （原始内容存档于2018-06-27）.
- ^ Pamudurti, Nagarjuna Reddy; Bartok, Osnat; Jens, Marvin; et al. Translation of CircRNAs. Molecular Cell. 2017, 66 (1): 9–21.e7. PMC 5387669 . PMID 28344080. doi:10.1016/j.molcel.2017.02.021.
- ^ Guo, J.U.; Agarwal, V; Guo, H; Bartel, DP. Expanded identification and characterization of mammalian circular RNAs. Genome Biology. 2014, 15 (7): 409. PMC 4165365 . PMID 25070500. doi:10.1186/s13059-014-0409-z.
- ^ 5.0 5.1 Wilusz, J.E.; Sharp, PA. A Circuitous Route to Noncoding RNA (PDF). Science. 2013, 340 (6131): 440–41. Bibcode:2013Sci...340..440W. PMC 4063205 . PMID 23620042. doi:10.1126/science.1238522.
- ^ 6.0 6.1 6.2 Jeck, WR; Sorrentino, JA; Wang, K; et al. Circular RNAs are abundant, conserved, and associated with ALU repeats.. RNA. 2013, 19 (2): 141–57. PMC 3543092 . PMID 23249747. doi:10.1261/rna.035667.112.
- ^ 7.0 7.1 Nisar, Sabah; Bhat, Ajaz A.; Singh, Mayank; Karedath, Thasni; Rizwan, Arshi; Hashem, Sheema; Bagga, Puneet; Reddy, Ravinder; Jamal, Farrukh; Uddin, Shahab; Chand, Gyan. Insights Into the Role of CircRNAs: Biogenesis, Characterization, Functional, and Clinical Impact in Human Malignancies. Frontiers in Cell and Developmental Biology. 2021-02-05, 9. ISSN 2296-634X. PMC 7894079 . PMID 33614648. doi:10.3389/fcell.2021.617281.
- ^ Zhang, Y; Zhang, XO; Chen, T; Xiang, JF; Yin, QF; Xing, YH; Zhu, S; Yang, L; Chen, LL. Circular Intronic Long Non-coding RNAs. Molecular Cell. 2013, 51 (6): 1–15. PMID 24035497. doi:10.1016/j.molcel.2013.08.017.
- ^ Ebert, MS; Sharp, PA. MicroRNA sponges: progress and possibilities. RNA. 2010, 16 (11): 2043–50. PMC 2957044 . PMID 20855538. doi:10.1261/rna.2414110.
- ^ Hansen, T.B.; Jensen, TI; Clausen, BH; Bramsen, JB; Finsen, B; Damgaard, CK; Kjems, J. Natural RNA circles function as efficient microRNA sponges. Nature. 2013, 495 (7441): 384–88. Bibcode:2013Natur.495..384H. PMID 23446346. doi:10.1038/nature11993.
- ^ Chen, CY; Sarnow, P. Initiation of protein synthesis by the eukaryotic translational apparatus on circular RNAs. Science. 1995, 268 (5209): 415–17. PMID 7536344. doi:10.1126/science.7536344.
- ^ Hentze, MW; Preiss, T. Circular RNAs: splicing's enigma variations. The EMBO Journal. 2013, 32 (7): 923–25. PMC 3616293 . PMID 23463100. doi:10.1038/emboj.2013.53.
- ^ Burd, CE; Jeck, WR; Liu, Y; Sanoff, HK; Wang, Z; Sharpless, NE. Expression of Linear and Novel Circular Forms of an INK4/ARF-Associated Non-coding RNA Correlates with Atherosclerosis Risk. PLOS Genetics. 2010, 6 (12): e1001223. PMC 2996334 . PMID 21151960. doi:10.1371/journal.pgen.1001233.
- ^ Dube, U; Del-Aguila, JL; Li, Z; Budde, JP; Jiang, S; Hsu, S; Ibanez, L; Fernandez, MV; et al. An atlas of cortical circular RNA expression in Alzheimer disease brains demonstrates clinical and pathological associations.. Nature Neuroscience. 2019, 22 (11): 1903–1912. PMC 6858549 . PMID 31591557. doi:10.1038/s41593-019-0501-5.
- ^ Harichandran K, Shen Y, Stephenson Tsoris S, Lee SC, Casey JL. Hepatitis Delta Antigen Regulates mRNA and Antigenome RNA Levels during Hepatitis Delta Virus Replication.. J Virol. 2019, 93 (8). PMC 6450126 . PMID 30728256. doi:10.1128/JVI.01989-18.
