Glycine-alanine dipeptide repeats (GA DPRs) translated from the mutated C9orf72 gene have recently been correlated with amyotrophic lateral sclerosis (ALS). While GA DPRs aggregates have been suggested as amyloid, the biophysical features and cytotoxicity of GA DPRs oligomers has not been explored due to its unstable nature. In this study, we develop a photoinducible platform based on methoxynitrobenzene chemistry to enrich GA DPRs that allows monitoring the oligomerization process of GA DPRs in cells. By applying advanced microscopies, we examined the GA DPRs oligomerization process nanoscopically in a time-dependent manner. We provided direct evidences to demonstrate GA DPRs oligomers rather than nanofibrils disrupt nuclear membrane. Moreover, we found GA DPRs hamper nucleocytoplasmic transport in cells and cause cytosolic retention of TAR DNA-binding protein 43 in cortical neurons. Our results highlight the toxicity of GA DPRs oligomers, which is a key step toward elucidating the pathological roles of C9orf72 DPRs.

从突变的C9orf72翻译的甘氨酸-丙氨酸二肽重复序列 (GA DPR)基因最近与肌萎缩性侧索硬化症 (ALS) 相关联。虽然 GA DPRs 聚集体被认为是淀粉样蛋白，但由于其不稳定的性质，尚未探索 GA DPRs 寡聚体的生物物理特征和细胞毒性。在这项研究中，我们开发了一个基于甲氧基硝基苯化学的光诱导平台来丰富 GA DPR，从而可以监测细胞中 GA DPR 的寡聚化过程。通过应用先进的显微镜，我们以时间依赖的方式在纳米显微镜下检查了 GA DPR 的寡聚化过程。我们提供了直接证据来证明 GA DPR 寡聚体而不是纳米原纤维破坏核膜。此外，我们发现 GA DPR 阻碍细胞核质转运，并导致皮层神经元中 TAR DNA 结合蛋白 43 的胞浆滞留。C9orf72 DPR。