Exploration of the modification of genomic higher-order structures in the cell nucleus by aggregation of chemically synthesized short nucleic acids

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K19040
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 37:Biomolecular chemistry and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Okamoto Akimitsu 東京大学, 大学院工学系研究科(工学部), 教授 (60314233)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 核酸 / 化学合成 / 集合体 / ハイブリダイゼーション / マイクロRNA / 相分離

Outline of Final Research Achievements

We have created a pair of chemically synthesized hairpin nucleic acids with sequences that form assemblies by sequential hybridization. In vitro experiments confirmed that these nucleic acid pairs form aggregates starting from miRNAs. When the nucleic acid pairs were added to HeLa cells together with a cell transfection agent, the nucleic acid pairs formed aggregates in the cytoplasm starting from miRNAs. Observation by fluorescence microscopy of FRET of the fluorescent labeling of the nucleic acids showed that they caused phase separation in the cytoplasm and formed droplet-like granules. Furthermore, FACS analysis revealed that strong FRET-derived fluorescence appeared in cells overexpressing the target miR-21, whereas FRET-derived fluorescence was weak in cells with low miR-21 expression.

Free Research Field

生物有機化学

Academic Significance and Societal Importance of the Research Achievements

今回の研究成果として、ヘアピン型人工核酸が細胞質内で相分離を引き起こすことやその原因が自然免疫関連タンパク質cGASの結合によること、さらにはその複合体形成が細胞死へ至らしめることが明らかになり、新たな部類の核酸医薬品のタネを見つけることができた。将来的には、化学合成ヘアピン型核酸対についてさらに検討を加えることによって他のタンパク質をトラップして効率的にノックダウンできる相分離系を作成したい。