Post-transcriptional regulation of gene expression in neuromuscular disease

描述(申请人提供)：强直性肌营养不良症(DM)是最常见的肌营养不良症，会导致所有肌肉类型的症状，表现为骨骼肌萎缩、心律失常和胃肠功能障碍。糖尿病是一种多系统疾病，通常还会影响中枢神经、内分泌和生殖系统。糖尿病是由扩大的CTG或CCTG重复序列引起的，这些重复序列被转录成RNA，隔离类似蝇眼(MBNL)的RNA结合蛋白，并将它们滴定到远离其正常的mRNA靶标。Cug重复表达还导致CUGBP/ELAV样因子(CELF)的过度磷酸化，导致CELF蛋白升高。MBNLS和CELFS的失调会导致数百种转录组的变化，包括许多选择性剪接的变化。到目前为止，DM的转录组变化的全谱仍然没有特征，也不知道MBNL和CELF的扰动是否能完全解释这些变化。此外，只有少数糖尿病症状的分子原因已被发现。MBNL蛋白介导的另一个细胞过程是RNA定位。RNA的亚细胞定位对许多细胞和生理过程非常重要，包括细胞运动、胚胎构型和突触功能。然而，我们对RNA定位的理解仍然局限于一小部分转录本，并且我们缺乏关于RNA如何实现定位的分子部分列表。对这些成员的识别将揭示RNA错误定位在多大程度上导致糖尿病和其他疾病的病理。因此，我们将系统地描述DM转录组的变化，并评估MBNL和CELF干扰在多大程度上可以解释DM转录组的这些变化(目标1)。我们将定义RNA本地化的部件列表，包括顺式和反式元件，并阐明这些参与者如何控制RNA的亚细胞分布(目标2)。我们将研究基因表达的所有步骤的变化，包括剪接、RNA定位和翻译，可能如何与DM表型联系起来，并开发治疗方法来纠正这些变化(目标3)。总之，这项工作的完成将进一步加深我们对糖尿病这一RNA毒性疾病的分子变化的理解，为更好地理解RNA定位奠定基础，并有助于将这些分子事件与生理联系起来。

DESCRIPTION (provided by applicant): Myotonic dystrophy (DM) is the most common form of muscular dystrophy, and leads to symptoms in all muscle types, in the form of skeletal muscle wasting, cardiac arrhythmias, and gastrointestinal dysfunction. A multi-systemic disease, DM also commonly affects the central nervous, endocrine, and reproductive systems. DM is caused by expanded CTG or CCTG repeats, which are transcribed into RNA, sequestering the Muscleblind- like (MBNL) RNA binding proteins and titrating them away from their normal mRNA targets. CUG repeat expression also leads to hyper-phosphorylation of the CUGBP/ ELAV-like factors (CELFs), resulting in CELF protein elevation. Dysregulation of MBNLs and CELFs causes hundreds of changes to the transcriptome, including many changes in alternative splicing. To date, the full spectrum of transcriptome changes in DM remains uncharacterized, and it is unknown whether MBNL and CELF perturbation can fully account for those changes. Furthermore, the molecular causes of only a few DM symptoms have been discovered. Another cellular process mediated by the MBNL proteins is RNA localization. Subcellular localization of RNA is important for numerous cellular and physiological processes, including cell motility, embryonic patterning, and synaptic function. However, our understanding of RNA localization remains restricted to a small subset of transcripts, and we lack a molecular parts list for how RNA localization is achieved. Identification of these players will reveal the extent to which RNA mis-localization contributes to pathology in DM and other diseases. Therefore, we will systematically characterize transcriptome changes in DM and assess the extent to which MBNL and CELF per- turbation can explain these changes in DM transcriptomes (Aim 1). We will define a parts list for RNA localization, including cis- and trans- elements, and elucidate how these players control subcellular distribution of RNAs (Aim 2). We will study how changes in all steps of gene expression, including splicing, RNA localization, and translation, may be linked to DM phenotypes, and develop therapeutic approaches to correct these changes (Aim 3). Together, completion of this work will further our understanding of the molecular changes in DM, a paradigm for diseases of RNA toxicity, lay the groundwork for better understanding RNA localization, and help connect these molecular events to physiology.