Regulation of Transcription by Circular RNAs
Regulation of Transcription by Circular RNAs
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DOI：
10.1007/978-981-13-1426-1_7
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发表时间：
2018-01-01
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影响因子：
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通讯作者：
Ain, Rupasri
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作者：
Bose, Rumela;Ain, Rupasri
环状RNA （circRNAs）是一类非编码RNA，存在于跨物种的各种组织类型的各种细胞中。它们是非聚腺苷化、单链、共价封闭的rna。由于缺乏5‘或3’端，CircRNAs比其他rna更稳定，从而导致对外切酶酶切的抵抗。环状rna的长度从1到5个外显子不等，成熟环状rna中内含子的保留频率约为25%。它们主要存在于细胞内的细胞质中，但其核输出的机制尚不清楚。然而，有一种circrna亚群仍然存在于细胞核中并调节rna - pol - ii介导的转录。挖掘RNA测序数据的生物信息学方法使环状RNA的全基因组鉴定成为可能。在哺乳动物基因组中，细胞和组织中超过20%的表达基因可以产生这些转录本。由于它们的丰度、稳定性和不同的表达谱，circRNAs可能在控制谱系决定、细胞分化和各种细胞类型功能的调控途径中发挥关键作用。然而，circrna介导的调控对各种细胞转录组的影响在很大程度上仍然未知。在本章中，我们将回顾环状rna在其自身或其他基因转录中的调节作用。此外，我们将讨论circrna与mirna和rna结合蛋白（rbp）的关联，特别提到果蝇circrna及其作为“mRNA陷阱”的作用，这可能在其转录或转录后的调控潜力中发挥作用。
Circular RNAs (circRNAs) are a class of noncoding RNA that are present in wide variety of cells in various tissue types across species. They are non-polyadenylated, single-stranded, covalently closed RNAs. CircRNAs are more stable than other RNAs due to lack of 5' or 3' end leading to resistance to exonuclease digestion. The length of circRNAs varies from 1 to 5 exons with retention of introns in mature circRNAs with similar to 25% frequency. They are primarily found in the cytosol within the cell although the mechanism of their nuclear export remains elusive. However, there is a subpopulation of circRNAs that remain in the nucleus and regulate RNA-Pol-II-mediated transcription. Bioinformatic approaches mining RNA sequencing data enabled genome-wide identification of circRNAs. In mammalian genome over 20% of the expressed genes in cells and tissues can produce these transcripts. Owing to their abundance, stability, and diverse expression profile, circRNAs likely play a pivotal role in regulatory pathways controlling lineage determination, cell differentiation, and function of various cell types. Yet, the impact of circRNA-mediated regulation on various cell transcriptome remains largely unknown. In this chapter, we will review the regulatory effects of circRNAs in the transcription of their own or other genes. Also, we will discuss the association of circRNAs with miRNAs and RNA-binding proteins (RBPs), with special reference to Drosophila circMbl and their role as an "mRNA trap," which might play a role in its regulatory potential transcriptionally or posttranscriptionally.