Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA.
RNA Biol. 2011 Jul-Aug;8(4):557-64. doi: 10.4161/rna.8.4.16019. Epub 2011 Jul 1.
The functional significance of microRNA-9 (miR-9) during evolution is evidenced by its conservation at the nucleotide level from flies to humans but not its diverse expression patterns. Recent studies in several model systems reveal that miR-9 can regulate neurogenesis through its actions in neural or non-neural cell lineages. In vertebrates, miR-9 exerts diverse cell-autonomous effects on the proliferation, migration, and differentiation of neural progenitor cells by modulating different mRNA targets. In some developmental contexts, miR-9 suppresses apoptosis and is misregulated in several types of cancer cells, influencing proliferation or metastasis formation. Moreover, downregulation of miR-9 in postmitotic neurons is also implicated in some neurodegenerative diseases. Thus, miR-9 is emerging as an important regulator in development and disease through its ability to modulate different targets in a manner dependent on the developmental stage and the cellular context.
微 RNA-9（miR-9）在从果蝇到人类的核苷酸水平上都得到了保守，但表达模式却多种多样，这证明了它在进化过程中的功能意义。最近在几个模型系统中的研究表明，miR-9 可以通过其在神经或非神经细胞谱系中的作用来调节神经发生。在脊椎动物中，miR-9 通过调节不同的 mRNA 靶标，对神经祖细胞的增殖、迁移和分化产生不同的细胞自主效应。在某些发育环境中，miR-9 抑制细胞凋亡，并且在几种类型的癌细胞中失调，影响增殖或转移形成。此外，在有丝分裂后神经元中的 miR-9 下调也与一些神经退行性疾病有关。因此，miR-9 通过其在发育阶段和细胞环境依赖的方式调节不同靶标，成为发育和疾病中的一个重要调节因子。
