Molecular, Cellular, and in vivo analysis of SLC12A2, a novel candidate of deafness gene

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K09336
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: 独立行政法人国立病院機構(東京医療センター臨床研究センター)
• Principal Investigator: MUTAI Hideki 独立行政法人国立病院機構(東京医療センター臨床研究センター), その他部局等, 研究員 (60415891)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 難聴 / 原因遺伝子 / スプライシング / 動物モデル

Outline of Final Research Achievements

Aim of this study is to analyze molecular dysfunction of variants of SLC12A2, a novel deafness gene that were identified in our group.
SLC12A2 encodes Na+, K+, 2Cl- cotransporter 1 and plays critical roles in the homeostasis of K+-enriched endolymph. All SLC12A2 candidate pathogenic variants mapped to exon 21 or its 3’-splice site. In this study, all the 3 projects achieved the goals successfully; 1) In vitro functional analysis demonstrated that Cl- influx was significantly decreased in all SLC12A2 variants studied. All variants were properly translocated to plasma membrane, suggesting proper protein folding without degeneration; 2) The in vitro assay system of exon 21 splicing was established; 3) Two mouse strains with each variant of Slc12a2 knocked in were generated by genome editing. Analysis of the KI mice are now ongoing in details.
SLC12A2 is now known as deafness gene DFNA78.

Free Research Field

耳科学

Academic Significance and Societal Importance of the Research Achievements

SLC12A2は、私たちが日本人難聴患者の遺伝子解析から同定した新規難聴原因候補である。本研究の成果により、SLC12A2が真の難聴遺伝子として認識され検査対象に追加されることで、難聴者の原因判明率の向上と、その知見をもととした適切な医療・療育の提供が期待できる。
SLC12A2の病的変異候補は、興味深いことに、すべてexon 21上ミスセンス変異あるいはexon 21のスプライス変異である。この部位の分子機構は未知であり、本研究および継続研究により、本遺伝子の詳細な機能が明らかとなり、学術的発展が期待できる。