Amyotrophic Lateral Sclerosis and the DNA Damage Response

肌萎缩性侧索硬化症（ALS）是由运动神经元过早/加速变性引起的。虽然一些ALS病例是散发的，分子原因未知，但其他病例是由于大约8个基因中的一个遗传显性突变。最近发现，由这些基因编码的一些蛋白质参与调节信使RNA （mRNA）的产生；这一过程被称为转录，基因在基因表达过程中被复制成mRNA。其中两种蛋白是肉瘤内融合/转位肉瘤（FUS/TLS）和TAR dna结合蛋白43 （TDP-43）。FUS/TLS和TDP-43与ALS的关联表明，在这种疾病的某些病例中，神经元细胞死亡可能涉及RNA加工中的功能缺失缺陷。然而，RNA加工在预防ALS中可能发挥的作用尚不清楚。我们现在提出了一个新的假设，并支持RNA加工如何预防ALS的初步证据。我们发现FUS/TLS和TDP-43在DNA损伤后重新分布，FUS在DNA损伤位点迅速积累，TDP-43迅速排出。我们发现，FUS/TLS和TDP-43的重新分配是一个活跃的过程，由在DNA损伤信号中具有既定作用的蛋白质调节，支持RNA加工是细胞DNA损伤反应的真正组成部分的观点。基于这些观察结果，我们提出FUS/TLS和TDP-43的RNA加工需要确保在DNA损伤存在时转录得到适当的管理和控制，并且这些和可能参与RNA加工的其他蛋白质的突变导致功能失调的基因表达和神经元细胞死亡。在这个应用中，我们计划使用分子和细胞方法的结合来直接解决这个假设。为此，我们将拟议的工作分为三个具体目标。我们会的，1。确定FUS/TLS和TDP-43在DNA损伤响应中重新分配的机制。2. 探讨FUS/TLS和TDP-43在DNA损伤信号传导和/或DNA损伤位点修复中的作用，以及这些蛋白如何在DNA损伤阻断这一过程的情况下调节转录。3. 研究FUS/TLS和TDP-43对细胞抵抗DNA损伤（包括运动神经元）的重要性，并确定DNA损伤反应过程中RNA加工的其他成分。

Amyotrophic Lateral Sclerosis (ALS) is caused by premature/accelerated degeneration of motor neurones. Whereas some cases of ALS are sporadic and of unknown molecular cause, others are due to hereditary dominant mutations in one of approximately eight genes. It has emerged recently that several of the proteins encoded by these genes are involved in regulating the production of messenger RNA (mRNA); a process known as transcription by which genes are copied into mRNA during gene expression. Two of these proteins are Fused-in-Sarcoma/Translocated-in-Sarcoma (FUS/TLS) and TAR DNA-binding protein 43 (TDP-43). The association of FUS/TLS and TDP-43 with ALS suggests that, in some cases of this disease, neuronal cell death may involve loss-of-function defects in RNA processing. However, the putative roles fulfilled by RNA processing that prevent ALS are unclear. We now present a novel hypothesis and supporting preliminary evidence for how RNA processing might prevent ALS. We show that FUS/TLS and TDP-43 are redistributed in response to DNA damage, with FUS rapidly accumulating at sites of DNA damage and TDP-43 rapidly expelled. We show that this redistribution of FUS/TLS and TDP-43 is an active process that is regulated by proteins with established roles in DNA damage signaling, supporting the idea that RNA processing is a bona fide component of the cellular DNA damage response. Based on these observations, we propose that RNA processing by FUS/TLS and TDP-43 is required to ensure that transcription is properly managed and controlled in the presence of DNA lesions, and that mutation of these and likely other proteins involved in RNA processing results in dysfunctional gene expression and neuronal cell death. In this application, we plan to address this hypothesis directly, using a combination of molecular and cellular approaches. To do this we have divided the proposed work into three specific objectives. We will, 1. Identify the mechanism/s by which FUS/TLS and TDP-43 are redistributed in response to DNA damage. 2. Address the role of FUS/TLS and TDP-43 in DNA damage signaling and/or repair at sites of DNA damage, and how these proteins regulate transcription in the presence of DNA lesions that block this process. 3. Examine the importance of FUS/TLS and TDP-43 for cellular resistance to DNA damage, including motor neurons, and identify additional components of RNA processing during the DNA damage response.