Loss of nuclear poly(A)-binding protein 1 causes defects in myogenesis and mRNA biogenesis
Loss of nuclear poly(A)-binding protein 1 causes defects in myogenesis and mRNA biogenesis
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DOI：
10.1093/hmg/ddp569
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发表时间：
2010-03-15
影响因子：
3.5
通讯作者：
Pavlath, Grace K.
中科院分区：
文献类型：
--
作者：
Apponi, Luciano H.;Leung, Sara W.;Pavlath, Grace K.
核多聚(A)结合蛋白1(PABPN1)是一种广泛表达的蛋白，在多聚腺苷化过程中起着关键作用。PABPN1 N末端聚丙氨酸束的短暂扩张导致眼咽肌营养不良症(OPMD)，OPMD是一种成人起病，以眼睑下垂、吞咽困难和四肢近端肌肉无力为特征。虽然来自体外生化分析的大量数据确定了PABPN1在控制聚(A)尾长方面的功能，但对PABPN1在哺乳动物细胞中的作用知之甚少。为了评估PABPN1在哺乳动物细胞中的功能，特别是在受OPMD影响的细胞中，我们使用siRNA检测了PABPN1缺失对原代小鼠眼外肌、咽肌和四肢肌成肌细胞的影响。PABPN1基因敲除显著抑制了体外成肌细胞的增殖和成肌细胞分化。在分子水平上，成肌细胞中PABPN1的缺失导致了mRNA Poly(A)尾巴的缩短，证明了PABPN1在哺乳动物细胞中的多聚腺苷酸化控制中的细胞功能。此外，PABPN1的耗尽导致Poly(A)RNA的核积累，表明PABPN1是正确的Poly(A)RNA从细胞核输出所必需的。综上所述，这些实验表明PABPN1在成肌细胞的增殖和分化中起着重要的作用，这表明它是体内肌肉再生和维持所必需的。
The nuclear poly(A)-binding protein 1 (PABPN1) is a ubiquitously expressed protein that plays a critical role in polyadenylation. Short expansions of the polyalanine tract in the N-terminus of PABPN1 lead to oculopharyngeal muscular dystrophy (OPMD), which is an adult onset disease characterized by eyelid drooping, difficulty in swallowing and weakness in the proximal limb muscles. Although significant data from in vitro biochemical assays define the function of PABPN1 in control of poly(A) tail length, little is known about the role of PABPN1 in mammalian cells. To assess the function of PABPN1 in mammalian cells and specifically in cells affected in OPMD, we examined the effects of PABPN1 depletion using siRNA in primary mouse myoblasts from extraocular, pharyngeal and limb muscles. PABPN1 knockdown significantly decreased cell proliferation and myoblast differentiation during myogenesis in vitro. At the molecular level, PABPN1 depletion in myoblasts led to a shortening of mRNA poly(A) tails, demonstrating the cellular function of PABPN1 in polyadenylation control in a mammalian cell. In addition, PABPN1 depletion caused nuclear accumulation of poly(A) RNA, revealing that PABPN1 is required for proper poly(A) RNA export from the nucleus. Together, these experiments demonstrate that PABPN1 plays an essential role in myoblast proliferation and differentiation, suggesting that it is required for muscle regeneration and maintenance in vivo.