Regulation of IZUMO1-JUNO in mammalian gamete fusion

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K15128
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Developmental biology
• Research Institution: Shizuoka University (2021); Fukushima Medical University (2017-2020)
• Principal Investigator: Saito Takako 静岡大学, 農学部, 助教 (10778038)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 受精 / 精子 / 卵子 / 膜融合 / IZUMO1 / JUNO

Outline of Final Research Achievements

Sperm-egg fusion is accomplished through interaction of a specific set of membrane proteins in each gamete: sperm IZUMO1 and oocyte JUNO. In this study, we produced mouse lines having different levels of IZUMO1 expression and point mutations in IZUMO1 for JUNO binding site by the CRISPR/Cas9 system. We observed that the mouse fertilization rate is highly affected by the density of IZUMO1 protein in sperm using gene modified mouse lines. These results suggest that evaluating IZUMO1 protein levels is useful for predicting fecundity, and suitable as a test for male fertility. Also we revealed that IZUMO1-JUNO interaction is essential for the beginning of gamete fusion.

Free Research Field

生殖生物学、発生生物学、細胞生物学

Academic Significance and Societal Importance of the Research Achievements

受精における膜融合は、同種異個体の細胞同士が融合するという他では例のない現象である。有性生殖の最大の利点である遺伝子の多様性を造り出すためにも、精子と卵子の融合は生物にとって最も重要な機構の一つである。IZUMO1-JUNOによって厳密に制御されている配偶子膜融合の解明を足がかりに、個体発生分化で起こる細胞間認識と融合の機構についても理解が広まると期待できる。