Obernosterer Gregor, Leuschner Philipp J F, Alenius Mattias, Martinez Javier
Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria.
RNA. 2006 Jul;12(7):1161-7. doi: 10.1261/rna.2322506. Epub 2006 May 31.
microRNAs (miRNAs) are endogenous, noncoding approximately 22-nucleotide RNA molecules that have recently emerged as fundamental, post-transcriptional regulators of cognate target gene expression. Many mammalian miRNAs are expressed in a tissue-specific manner, a phenomenon that has so far been attributed to transcriptional regulation. We here show by Northern blots and in situ hybridization experiments that the expression of mammalian miRNAs can be regulated at the post-transcriptional level. In particular, miR-138 is spatially restricted to distinct cell types, while its precursor, pre-miR-138-2, is ubiquitously expressed throughout all tissues analyzed. Furthermore, pre-miR-138-2 is exported from the nucleus to the cytoplasm, suggesting that cleavage of this pre-miRNA by Dicer is restricted to certain tissues and cell types. Thus, differential processing of pre-miRNAs might be an alternative mechanism to control miRNA function.
微小RNA（miRNA）是内源性的、约22个核苷酸的非编码RNA分子，最近已成为同源靶基因表达的基本转录后调节因子。许多哺乳动物miRNA以组织特异性方式表达，迄今为止，这种现象被归因于转录调控。我们通过Northern印迹和原位杂交实验表明，哺乳动物miRNA的表达可以在转录后水平受到调控。特别是，miR-138在空间上局限于不同的细胞类型，而其前体pre-miR-138-2在所有分析的组织中普遍表达。此外，pre-miR-138-2从细胞核输出到细胞质，这表明Dicer对该前体miRNA的切割仅限于某些组织和细胞类型。因此，前体miRNA的差异加工可能是控制miRNA功能的另一种机制。
