Stimulating SMN2 exon 7 inclusion with short RNAs

描述（由申请方提供）：脊髓性肌萎缩症（SMA）是一种常染色体隐性遗传神经退行性疾病，是婴儿死亡的最常见遗传原因。 SMA决定基因位于染色体5 q上，被称为运动神经元存活基因1（SMN 1）。 值得注意的是，存在一个几乎相同的拷贝基因，称为SMN 2。 该基因具有编码与SMN 1相同的蛋白质的能力，然而，由于单个沉默的非多态性核苷酸差异，大多数SMN 2衍生的转录物被选择性剪接，并编码截短的和生化缺陷的蛋白质，称为SMN？7. 迄今为止，SMN 2是唯一的SMA修饰基因。 轻度表型与SMN 2拷贝数增加相关，通常为2 - 4个拷贝。 SMA的遗传背景使这种疾病特别适合治疗干预，包括：SMN 2在基本上所有SMA患者中保留; SMN 2在所有组织中普遍表达; SMN 2保留编码正常全长SMN蛋白的能力。 因此，SMN 2已被确定为潜在SMA治疗的主要靶点。 最有吸引力的可能性包括刺激总SMN 2转录和/或调节SMN 2选择性剪接事件。 为了利用独特的SMA遗传背景，本申请的目标是开发调节SMN 2剪接的新型RNA。 通过使用病毒递送系统（Aim 1），将在旨在鉴定诱导最高水平全长SMN 2表达的RNA的各种实验环境中检查这些RNA（Aim 1和2）。 然后将在SMA小鼠模型中检查最佳候选RNA，以确定RNA是否可以调节生物体中的SMN 2，以及全长SMN 2表达的预期增加是否会减少转基因小鼠中充分描述的轻度SMA表型（目的3）。 虽然本申请中描述的实验对SMA疗法的开发具有直接影响，但结果可用作广泛的遗传疾病的模型，其中校正剪接缺陷将恢复致病基因的功能。

DESCRIPTION (provided by applicant): Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder and is the most common genetic cause of infantile death. The SMA-determining gene is located on chromosome 5q, and is called survival motor neuron-1 (SMN1). Remarkably, a nearly identical copy gene is present called SMN2. This gene has the capacity to encode an identical protein compared to SMN1, however, due to a single silent non-polymorphic nucleotide difference, the majority of SMN2-derived transcripts are alternatively spliced and encode a truncated and biochemically defective protein called SMN?7. To date, SMN2 is the only SMA modifying gene. Milder phenotypes correlate with an increase in the number of SMN2 copies, typically ranging from two to four copies. The genetic context of SMA makes this disease especially amenable to therapeutic intervention including: SMN2 is retained in essentially all SMA patients; SMN2 is ubiquitously expressed in all tissues; and SMN2 retains the capacity to encode a normal, full-length SMN protein. Therefore, SMN2 has been identified as a major target for a potential SMA therapies. The most attractive possibilities include stimulating total SMN2 transcription and/or modulation of the SMN2 alternative splicing event. To take advantage of the unique SMA genetic context, the goal of this application is to develop novel RNAs that modulate SMN2 splicing. Through the use of a viral delivery system (Aim 1), these RNAs will be examined in a variety of experimental contexts designed to identify RNAs that induces the highest level of full-length SMN2 expression (Aim 1 and 2). The top candidate RNAs will then be examined in a murine model of SMA to determine whether the RNAs can modulate SMN2 in an organism and whether this expected increase in full-length SMN2 expression lessens the well described mild SMA phenotype in transgenic mice (Aim 3). While the experiments described in this application have immediate implications for the development of a SMA therapy, the results could be used as a model for a broad range of genetic disorders in which correcting a splicing defect would restore functionality to a disease-causing gene.