Oguro Akihiro, Uemura Takeshi, Machida Kodai, Kitajiri Kanta, Tajima Ayasa, Furuchi Takemitsu, Kawai Gota, Imataka Hiroaki
Division of Physical Fitness, Department of Molecular Physiology, The Jikei University School of Medicine, Tokyo, Japan.
Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, Saitama, Japan.
J Biol Chem. 2025 Mar;301(3):108251. doi: 10.1016/j.jbc.2025.108251. Epub 2025 Jan 31.
Repeat expansion disorders are caused by abnormal expansion of microsatellite repeats. Repeat-associated non-AUG (RAN) translation is one of the pathogenic mechanisms underlying repeat expansion disorders, but the exact molecular mechanism underlying RAN translation remains unclear. Polyamines are ubiquitous biogenic amines that are essential for cell proliferation and cellular functions. They are predominantly found in cells in complexes with RNA and influence many cellular events, but the relationship between polyamines and RAN translation is yet to be explored. Here, we show that, in both a cell-free protein synthesis system and cell culture, polyamines promote RAN translation of RNA-containing CCUG repeats. The CCUG-dependent RAN translation is suppressed when cells are depleted of polyamines but can be recovered by the addition of polyamines. Thermal stability analysis revealed that the tertiary structure of the CCUG-repeat RNA is stabilized by the polyamines. Spermine was the most effective polyamine for stabilizing CCUG-repeat RNA and enhancing RAN translation. These results suggest that polyamines, particularly spermine, modulate RAN translation of CCUG-repeat RNA by stabilizing the tertiary structure of the repeat RNA.
重复序列扩增疾病是由微卫星重复序列的异常扩增引起的。重复序列相关的非AUG（RAN）翻译是重复序列扩增疾病的致病机制之一，但RAN翻译的确切分子机制仍不清楚。多胺是普遍存在的生物胺，对细胞增殖和细胞功能至关重要。它们主要存在于与RNA结合的细胞复合物中，并影响许多细胞事件，但多胺与RAN翻译之间的关系尚待探索。在这里，我们表明，在无细胞蛋白质合成系统和细胞培养中，多胺都能促进含CCUG重复序列的RNA的RAN翻译。当细胞内多胺耗尽时，CCUG依赖性RAN翻译受到抑制，但添加多胺后可恢复。热稳定性分析表明，多胺可稳定CCUG重复序列RNA的三级结构。精胺是稳定CCUG重复序列RNA和增强RAN翻译最有效的多胺。这些结果表明，多胺，尤其是精胺，通过稳定重复序列RNA的三级结构来调节CCUG重复序列RNA的RAN翻译。
