MicroRNAs (miRNAs) are a class of small non-coding RNAs that play increasingly appreciated roles in gene regulation. In animals, miRNAs silence gene expression by binding to partially complementary sequences within target mRNAs. It is well-established that miRNAs recognize canonical target sites by base-pairing in the 5'region. However, the development of biochemical methods has identified many novel, non-canonical target sites, suggesting additional modes of miRNA-target association. Here, we review the current knowledge of miRNA-target recognition and how new evidence supports or challenges existing models. We also review the process by which microRNA isoforms achieve functional diversification via modulation of target recognition.

中文翻译：

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IsomiRs：将 miRNA 抑制工具箱扩展到种子之外。

MicroRNA (miRNA) 是一类小型非编码 RNA，在基因调控中发挥着越来越重要的作用。在动物中，miRNA 通过与目标 mRNA 内的部分互补序列结合来沉默基因表达。众所周知，miRNA 通过 5' 区域的碱基配对来识别典型靶位点。然而，生化方法的发展已经确定了许多新颖的、非规范的靶位点，这表明了 miRNA-靶标关联的其他模式。在这里，我们回顾了 miRNA 靶标识别的当前知识以及新证据如何支持或挑战现有模型。我们还回顾了 microRNA 同种型通过调节目标识别实现功能多样化的过程。