miRNA的异构体——isomiR

最近,深度测序技术揭示:同一个miRNA前体可能由于Drosha或Dicer的剪切位点改变,外切核酸酶介导的miRNA末端缩短,miRNA编辑或miRNA 3'末端无需模板的核苷酸添加等4种原因,而形成多种长度或序列不同的miRNAs异构体—isomiR.因为这些isomiR与已注解的miRNA可以调节同一个靶标,也可以靶向不同的靶标,所以它们不仅扩大了miRNA调节的范围,而且还有可能代表了每种miRNA基于isomiR的一种微型调节网络.研究发现,isomiR的表达具有细胞、组织、发育和疾病状况等特异性,并且很多人类疾病的致病机制也与它们有关,推测isomiR将来不仅有可能成为疾病诊断或治疗的生物学标记或靶标,而且相关的研究还对于RNA干扰技术也具有重要的指导意义.本文主要综述了isomiR的研究进展,并对isomiR应用前景做了展望.

The Isoforms of MiRNA—IsomiR

Recently, the deep sequencing revealed that the same miRNA precursor can generate multiple isoforms of miRNA, named isomiR, which vary in length and/or sequence, due to a shift of cleavage sites of Drosha and Dicer, exonuclease mediated trimming, miRNA editing, or 3′ end nontemplated nucleotide addition. These isomiR can act coordinately to target the same genes as canonical miRNA or redirect targeting to a dramatically different gene, so they not only broaden the regulatory range of the miRNA, they may also represent a deeper miRNA regulatory network based on isomiR. It has been found that the expression of isomiR is often cell, tissue, development, disease condition specific, and they are involved in the pathogenesis of many human diseases, such as Type 2 Diabetes and cancer. It is likely that isomiR not only will be used as a diagnostic biomarker or new therapeutic target, but also has great aplication for RNAi technology. In this review, recent achievements of isomiR will be discussed. The application perspective of isomiR will also be speculated.