Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, UK.
Nat Struct Mol Biol. 2012 Aug;19(8):760-6. doi: 10.1038/nsmb.2344. Epub 2012 Jul 15.
The Drosha-DGCR8 complex (Microprocessor) is required for microRNA (miRNA) biogenesis. DGCR8 recognizes the RNA substrate, whereas Drosha functions as the endonuclease. Using high-throughput sequencing and cross-linking immunoprecipitation (HITS-CLIP) we identified RNA targets of DGCR8 in human cells. Unexpectedly, miRNAs were not the most abundant targets. DGCR8-bound RNAs also comprised several hundred mRNAs as well as small nucleolar RNAs (snoRNAs) and long noncoding RNAs. We found that the Microprocessor controlled the abundance of several mRNAs as well as of MALAT1. By contrast, DGCR8-mediated cleavage of snoRNAs was independent of Drosha, suggesting the involvement of DGCR8 in cellular complexes with other endonucleases. Binding of DGCR8 to cassette exons is a new mechanism for regulation of the relative abundance of alternatively spliced isoforms. These data provide insights in the complex role of DGCR8 in controlling the fate of several classes of RNAs.
Drosha-DGCR8 复合物（微处理器）是 miRNA（miRNA）生物发生所必需的。DGCR8 识别 RNA 底物，而 Drosha 则作为内切酶发挥作用。我们使用高通量测序和交联免疫沉淀（HITS-CLIP）鉴定了人类细胞中 DGCR8 的 RNA 靶标。出乎意料的是，miRNA 不是最丰富的靶标。DGCR8 结合的 RNA 还包括数百个 mRNA 以及小核仁 RNA（snoRNA）和长非编码 RNA。我们发现微处理器控制着几种 mRNA 以及 MALAT1 的丰度。相比之下，DGCR8 介导的 snoRNA 切割不依赖于 Drosha，这表明 DGCR8 参与了与其他内切酶的细胞复合物。DGCR8 与盒外显子的结合是调节选择性剪接异构体相对丰度的新机制。这些数据为 DGCR8 在控制几类 RNA 命运方面的复杂作用提供了深入了解。
