Sperm recognition domain in mammalian egg coat matrix

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K06961
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Chiba University
• Principal Investigator: Yonezawa Naoto 千葉大学, 大学院理学研究院, 准教授 (80212314)
• Co-Investigator(Kenkyū-buntansha): 柳田 光昭 順天堂大学, 医学(系)研究科(研究院), 准教授 (80365569)
• Co-Investigator(Renkei-kenkyūsha): TANOKURA MASARU 東京大学, 農学生命科学研究科, 特任教授 (60136786)
• Project Period (FY): 2015-10-21 – 2018-03-31
• Keywords: 糖タンパク質 / 受精 / 透明帯 / Sf9細胞 / タンパク質複合体

Outline of Final Research Achievements

Bovine egg coat is a sponge-like matrix consisting of three glycoproteins called ZP2, ZP3 and ZP4. In a competitive inhibition assay, each of the three glycoproteins does not inhibit the binding of sperm to the egg coat but only ZP3/ZP4 complex inhibits the binding. We found that the region from Trp-156 to Arg-160 existing in the flexible hinge region of ZP3 is involved in the complex formation with ZP4 and moreover that an N-glycan linked to Asn-146 of ZP3 is involved in sperm-binding activity of ZP3/ZP4 complex. We established a new sperm-binding assay technique by which we can detect sperm-binding activity of each single component. By utilizing this technique, we found that among the three components only ZP4 has sperm-binding activity and moreover that glycans linked to ZP4 are not necessary for the activity. Thus, it is suggested that not only glycans but also polypeptide moieties of egg coat glycoproteins are involved in sperm-binding activity in bovine.

Free Research Field

構造生物化学