Canonical and alternate functions of the microRNA biogenesis machinery
Canonical and alternate functions of the microRNA biogenesis machinery
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DOI：
10.1101/gad.1953310
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发表时间：
2010-09-10
影响因子：
10.5
通讯作者：
Littman, Dan R.
中科院分区：
文献类型：
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作者：
Chong, Mark M. W.;Zhang, Guoan;Littman, Dan R.
标准microRNA （miRNA）生物发生途径需要两种RNaseIII酶：Drosha和Dicer。为了了解它们在哺乳动物体内的功能，我们对小鼠进行了种系或组织特异性灭活，使编码这两种蛋白质的基因失活。dicer和drosha缺陷小鼠的蛋白质组学和转录谱的变化证实了这两种酶在标准miRNA生物发生中的必要性。然而，缺乏Drosha或Dicer并不总是导致相同的表型，这表明有额外的功能。我们发现，在早期胸腺细胞中，Drosha识别并直接切割许多具有次级茎环结构的蛋白质编码信使rna （mrna）。此外，我们确定了由dicer依赖但不依赖drosha机制产生的mirna子集。它们不同于先前描述的反射镜。因此，在哺乳动物细胞中，Dicer是多种mirna的生物发生所必需的。总之，这些发现扩展了RNaseIII酶的功能范围，超出了典型的miRNA生物发生，并有助于解释由Drosha和Dicer缺陷引起的非重叠表型。
The canonical microRNA (miRNA) biogenesis pathway requires two RNaseIII enzymes: Drosha and Dicer. To understand their functions in mammals in vivo, we engineered mice with germline or tissue-specific inactivation of the genes encoding these two proteins. Changes in proteomic and transcriptional profiles that were shared in Dicer-and Drosha-deficient mice confirmed the requirement for both enzymes in canonical miRNA biogenesis. However, deficiency in Drosha or Dicer did not always result in identical phenotypes, suggesting additional functions. We found that, in early-stage thymocytes, Drosha recognizes and directly cleaves many protein-coding messenger RNAs (mRNAs) with secondary stem-loop structures. In addition, we identified a subset of miRNAs generated by a Dicer-dependent but Drosha-independent mechanism. These were distinct from previously described mirtrons. Thus, in mammalian cells, Dicer is required for the biogenesis of multiple classes of miRNAs. Together, these findings extend the range of function of RNaseIII enzymes beyond canonical miRNA biogenesis, and help explain the nonoverlapping phenotypes caused by Drosha and Dicer deficiency.