Involvement of FMRP in Primary MicroRNA Processing via Enhancing Drosha Translation
Involvement of FMRP in Primary MicroRNA Processing via Enhancing Drosha Translation
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FMRP 通过增强 Drosha 翻译参与初级 MicroRNA 加工
DOI：
10.1007/s12035-016-9855-9
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发表时间：
2017-05-01
影响因子：
5.1
通讯作者：
Long, Yue-Sheng
中科院分区：
文献类型：
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作者：
Wan, Rui-Ping;Zhou, Lin-Tao;Long, Yue-Sheng
脆性X智力低下蛋白(FMRP)与脆性X综合征相关，是一种RNA结合蛋白，在脑内转录后水平调节基因表达。在前体miRNA(前-miRNA)转化为成熟miRNA的过程中，FMRP也参与了microRNA(MiRNA)的生物发生。然而，没有关于FMRP对初级miRNA(pri-miRNA)加工的影响的描述。在这里，我们通过控制DROSHA翻译揭示了FMRP在pri-miRNA处理中的一个新角色。我们发现，在Fmr1基因敲除小鼠的海马区和FMRP基因敲除的Neuro-2a细胞中，DROSHA蛋白的表达下调，而不是其信使RNA(MRNA)转录本。过表达或敲除FMRP不会改变DROSHA mRNA的稳定性。免疫沉淀和多聚体分析表明，FMRP与DROSHA mRNA结合并增强其翻译。此外，我们发现Fmr1缺陷小鼠的FMRP丢失导致六分之三的pri-miRNAs积累，相应的前miRNAs和成熟miRNAs减少。因此，我们的数据表明，FMRP通过促进DROSHA的表达参与了pri-miRNA的加工，这可能在脆性X综合征中发挥重要作用。
Fragile X mental retardation protein (FMRP), associated with fragile X syndrome, is known as an RNA-binding protein to regulate gene expression at post-transcriptional level in the brain. FMRP is also involved in microRNA (miRNA) biogenesis during the process of precursor miRNA (pre-miRNA) into mature miRNA. However, there is no description of the effect of FMRP on primary miRNA (pri-miRNA) processing. Here, we uncover a novel role of FMRP in pri-miRNA processing via controlling Drosha translation. We show that the expression of DROSHA protein, instead of its messenger RNA (mRNA) transcripts, is downregulated in both the hippocampus of Fmr1-knockout mice and the FMRP-knockdown Neuro-2a cells. Overexpression or knockdown FMRP does not alter Drosha mRNA stability. Immunoprecipitation and polysome analyses demonstrate that FMRP binds to the Drosha mRNA and enhances its translation. Additionally, we show that loss of FMRP in Fmr1-deficient mice results in the accumulation of three in six analyzed pri-miRNAs and the reduction of the corresponding pre-miRNAs and mature miRNAs. Thus, our data suggest that FMRP is involved in pri-miRNA processing via enhancing DROSHA expression that may play an important role in fragile X syndrome.