Molecular analysis of fertilization competence of egg-coating structures

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K07305
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 48020:Physiology-related
• Research Institution: Saitama Medical University
• Principal Investigator: Miwa Naofumi 埼玉医科大学, 医学部, 教授 (40255427)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 受精 / 卵保護膜

Outline of Final Research Achievements

Fertilization begins with proper interaction between fertilization-competent egg-coating structure and sperm. The molecular properties conferring fertilization competence to egg-coating structure remain largely unknown. We identified a novel mediator of fertilization, dicalcin, in the egg-coating envelope of Xenopus laevis. We have also found that mouse dicalcin is present in the cumulus cell-oocyte complex prepared from the oviduct lumen following ovulation. Here, we investigated the mechanism for suppressive action of dicalcin as well as its in vivo function. We found the presence of a soluble protein that bound to fluorescently-labeled dicalcin in two-dimensional electrophoresis experiment. The number of naturally born pups from DC(-/-) female mice was significantly greater than those of wild type throughout the ages examined. Thus, dicalcin physiologically regulates the fertilization success in vivo via binding to several target molecules.

Free Research Field

生理学

Academic Significance and Societal Importance of the Research Achievements

受精成立には、卵を取り囲む構造物(卵保護膜と呼ばれる)と精子が適切に作用することが必要である。これまでに、卵保護膜に存在するタンパク質（ダイカルシンと名称）が、卵保護膜の糖タンパク質に結合し、卵保護膜の物性を調節し受精成立に関与することを明らかにしてきた。本研究では、ダイカルシンの受精制御の分子基盤と生理機能を検証し、標的タンパク質の存在を明らかにし、またダイカルシン遺伝子欠損マウスの妊孕性が野生型よりも増強することを示唆する結果を得た。本研究成果を応用することで、ヒトを含む様々な動物における生殖補助技術の開発に進歩を促す可能性が考えられる。