Analysis of generation mechanisms of somatic revertant mutations and development of their control methods aiming at new cell medicine strategy

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K19540
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 53:Organ-based internal medicine and related fields
• Research Institution: Nagoya University
• Principal Investigator: AKIYAMA Masashi 名古屋大学, 医学系研究科, 教授 (60222551)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: 遺伝子 / 体細胞復帰変異 / モザイク / 魚鱗癬 / 表皮

Outline of Final Research Achievements

In this study, we focused on ichthyosis with confetti (IWC), a subtype of epidermolytic ichthyoses caused by heterozygous KRT1 or KRT10 mutations. In this disease, somatic revertant mosaicism occurs at an abnormally high frequency. Healthy tissue made by somatic revertant mosaicism is ideal as a cell medicine because it consists of the patient's own cells and does not have immunogenicity. In IWC, mutations are concentrated in specific regions of the causative genes KRT1 and KRT10, but the reason why the somatic revertant mosaicism occurs frequently is unknown. Since the genome size of KRT1 is as small as about 4.5 kb and it is extremely suitable for genetic manipulation. In this study, we tried to create a model cell line and a model animal system of IWC by introducing heterozygous gene mutations into the KRT1 gene by CRISPR-Cas9, and aimed to elucidate the molecular mechanism of the somatic revertant mosaicism using those systems.

Free Research Field

皮膚科学

Academic Significance and Societal Importance of the Research Achievements

本研究ではichthyosis with confetti（IWC）のモデル実験系の作成を目指し、体細胞復帰突然変異によるモザイク現象を人為的に発生させる技術の創出を目標とした。IWCにおいて体細胞復帰突然変異によるモザイク現象が多発する事は、mitotic recombinationの発生頻度を調節する未知のメカニズムが細胞内に存在する事を示している。その意義は不明であるが、病的遺伝子存在下での個体の健全性を担保している可能性が示唆される。mitotic recombinationの発生頻度を調節する未知のメカニズムが解明されれば、細胞生物学的に新しい概念が提示されることになる。