Tetrachromatic vision-specific miRNA: its role in evolution and regulation of color vision in vertebrates

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19280
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
• Research Institution: Konan University
• Principal Investigator: Kusakabe Takehiro 甲南大学, 理工学部, 教授 (40280862)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 色覚 / 錐体視細胞 / miRNA / メダカ / 進化

Outline of Final Research Achievements

We performed a comprehensive survey of vertebrate genomes for a microRNA (miR-726) specifically expressed in cone photoreceptor cells of the retina of birds and fish with tetrachromatic color vision. We found that mutations in the miR-726 sequence occurred independently in several lineages of fish, birds, and reptiles and that they could be associated with ecological characteristics. Various miR-726 mutants of medaka fish, including loss of function mutations, were generated by the CRISPR/Cas9 genome editing method, and comparative analysis between the mutants and wild-type strains was performed. Alterations in the expression of various genes involved in vision were detected in the mutants.

Free Research Field

発生生物学、神経生物学、進化生物学

Academic Significance and Societal Importance of the Research Achievements

色覚の進化過程においては、単にオプシン遺伝子の数や配列が変化するだけでなく、シグナル伝達系や遺伝子発現、細胞形質、細胞間ネットワーク、行動等、さまざまな変化が生じていると考えられる。miRNAは特定の生命現象に関連する多くの遺伝子の発現を同時に制御するため、本研究で見出された標的遺伝子が、他のアプローチではみつけることが困難な色覚関連遺伝子の発見につながることが期待される。また、本研究の成果に基づく解析を更に進めることで、４色型色覚をもつ陸上脊椎動物の共通祖先から哺乳類への進化の過程で失われた機能と、人類があらたに獲得した色覚の特性の理解につながることが期待される。