Studies on the sperm extracellular ubiquitin-proteasome system involved in fertilization

2016 Fiscal Year Final Research Report

• Project/Area Number: 25291024
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Functional biochemistry
• Research Institution: Nagoya University
• Principal Investigator: Sawada Hitoshi 名古屋大学, 理学(系)研究科(研究院), 教授 (60158946)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 受精 / ユビキチン / プロテアソーム / 精子 / 細胞外

Outline of Final Research Achievements

We previously reported that the extracellular ubiquitin-proteasome system may be involved in fertilization of the ascidian Halocynthia roretzi. Here, we cloned two cDNAs of ubiquitin-activating enzymes (E1), HrUBA1 and HrUBA6 and showed that these mRNAs are expressed in most organs, including the ovary and testis. Immunocytochemistry using peptide antibodies revealed that these enzymes are localized on follicle cells of the eggs and on sperm head around a mitochondrion. E1 inhibitor PYR-41 inhibited fertilization, suggesting that gamete E1s may be involved in fertilization. We also studied on the sperm proteasome by using a peptide antibody against sperm proteasome. The results showed that the sperm proteasome is localized on the surface of sperm head over a mitochondrion. Since anti-proteasome antibodies inhibited fertilization, it was suggested that the sperm proteasome plays a key extracellular role in fertilization.

Free Research Field

生化学