Elucidation of the molecular mechanism involved in mammalian gamete fusion

2017 Fiscal Year Final Research Report

• Project/Area Number: 26291052
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Developmental biology
• Research Institution: Fukushima Medical University
• Principal Investigator: Inoue Naokazu 福島県立医科大学, 医学部, 准教授 (50379096)
• Co-Investigator(Renkei-kenkyūsha): WADA Ikuo 福島県立医科大学, 医学部, 教授 (40182969) ; MIYADO Kenji 独立行政法人国立生育医療研究センター, 生殖・細胞医療研究部, 室長 (60324844) ; HAGIHARA Yoshihisa 独立行政法人産業技術総合研究所, 創薬基盤研究部門, 副研究部門長 (50357761)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 受精 / 精子 / 卵子 / 膜融合 / IZUMO1 / JUNO

Outline of Final Research Achievements

When a spermatozoon fertilizes an oocyte in mammals, there must be an extremely precise regulation system for successful gamete fusion to occur, which is the final step of fertilization. Sperm-egg fusion is considered to consist of multiple steps. As a reason for that using gene-modified animals, IZUMO1 and SPACA6 on the sperm side and IZUMO1-receptor JUNO and CD9 on the ovum side have been unveiled as indispensable factors for triggering gamete fusion, however, the functional relationships among each factor are still unclear. Furthermore, we have also established an in vitro cell-oocyte binding system, in which cultured cells expressing the Izumo1 gene, such as COS-7 cells, become adhesion-competent towards oocytes. However, because COS-7 cells solely expressing the Izumo1 gene never acquire membrane fusion activity with oocytes, the detailed molecular mechanisms leading to gamete membrane fusion also remain elusive.

Free Research Field

生殖生物学