| Budget Amount *help |
¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2015: ¥8,320,000 (Direct Cost: ¥6,400,000、Indirect Cost: ¥1,920,000)
Fiscal Year 2014: ¥8,320,000 (Direct Cost: ¥6,400,000、Indirect Cost: ¥1,920,000)
Fiscal Year 2013: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| 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.
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