Elucidation of the ubiquitination pathway mediating recruitment of SLX4 during ICL repair

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K12822
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Kyoto University
• Principal Investigator: Katsuki Yoko 京都大学, 生命科学研究科, 特定助教 (00645377)
• Research Collaborator: ABE masako
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: ユビキチン化 / ICL修復 / フォーカス形成

Outline of Final Research Achievements

Mutations in the SLX4 gene cause Fanconi anemia (FA-P). SLX4 encodes a large scaffold protein that possesses ubiquitin-binding domain and contributes to DNA interstrand crosslink (ICL) repair. Its recruitment to DNA damage site is required for ICL repair, and is mediated by an unidentified ubiquitination pathway.
To elucidate mechanisms to recruit SLX4 to the ICL lesion, we first determined SLX4 amino acid residues essential for the recruitment during ICL repair. Using GFP fusion with this region of SLX4, we carried out siRNA screening to find novel factors that are required for SLX4 recruitment to damage site and identified E3 ubiquitin ligase RNF168, which is known to function in DNA repair pathways. However, any components of the FA core complex or FANCD2 were not found as a hit candidate in our screening. Thus we concluded that SLX4 might be recruited to ICL site by a mechanism dependent on RNF168-mediated ubiquitination but independent on the canonical FA pathway during ICL repair.

Free Research Field

DNA修復

Academic Significance and Societal Importance of the Research Achievements

SLX4集積に必要なユビキチン結合ドメインの欠損はファンコニ貧血(FA)を引き起こすため、その集積メカニズムは、FAの発症抑制に密接にかかわっている。このメカニズムを明らかにすることは、ゲノムの安定性や造血幹細胞の維持に役立つと考えられ、本課題にアプローチするための実験系を構築し、新規因子を同定したことに、本研究の学術的意義があるといえる。またファンコニ貧血をモデルとしたICL修復の研究を基に、内因性の化学物質がゲノム不安定性を引き起こすことで発がんに至るメカニズムをあきらかにすることは、広くがんの発生、予防や治療を考察するうえでも貴重な検討材料となり、社会的貢献につながると考えられる。