| Project/Area Number |
02455022
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Showa University |
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Principal Investigator |
INOUE Sadako Showa University, School of Pharmaceutical Sciences Associate Professor, 薬学部, 助教授 (00053827)
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| Co-Investigator(Kenkyū-buntansha) |
IWASAKI Mariko Showa University, School of Pharmaceutical Sciences Assistant, 薬学部, 助手 (80054021)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 1992: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | Embryogenesis / Vitellogenesis / De-N-Glycosylation / Peptide:N-Glycanase / PNGase / Phosvitin / Hyosophorin / Post-Translational Remodification / 動物グリコペプチダ-ゼ / DeーNーglycosylation / Nーグリコシド型糖鎖 / 糖タンパク質代謝 / メダカ卵 / リン酸化糖タンパク質 / 表層胞糖タンパク質 / 動物糖タンパク質糖鎖の遊離 / 魚卵ビテロジェニン / 魚卵ホスビチン糖鎖 / 糖タンパク質糖鎖の代謝機構 |
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| Research Abstract |
Glycoproteins play important functions in many cellular processes of multi-cellular organisms. Compared to the intensive studies on the mechanism of protein N-glycosylation, those on the metabolism of N-glycans have been poor, though the latter is also important for understanding the significance of N-glycosylation.
This research project is originated from our recent findings of accumulation of free glycoprotein-derived glycan chains in the unfertilized eggs and the embryos of certain fishes. The structural studies suggested that the parent glycoproteins of the free glycan chains found in the unfertilized eggs and those found in the embryos were different with respect to the localization and function. Nevertheless these free glycan chains have the following common features: (1) they have di-N-acetylchitobiose structure at their reducing termini, and (2) they retain complete complex-type multi-antennary structures of which the peripheral portions are species-specific.
The new findings obt
… More
ained by this research are: (1) Peptide:N-glycanase (PNGase) activity was identified and partially purified from the early embryos of Oryzias latipes (Medaka fish). This was the first demonstration of the presence of PNGase activity in animal cells. (2) The progenitors of free glycans accumulated in the unfertilized eggs of three species of fish were identified to be glycophosphoproteins (phosvitins) by structural elucidation of the N-linked glycan chains of the glycophosphoprotein isolated from each species of fish. (3) The accumulation of the free glycan chain liberated from the cortical alveolar glycoprotein (hyosophorin) was shown during early embryogenesis of Medaka fish. The appearance of the free glycan was noted at the stage of morula and the amount increased up to the stage of gastrulation. (4) Partially purified PNGase from Oryzias can liberate glycans from the glycophosphoprotein and the hyosophorin of this fish: the results show that these glycoproteins are the physiological substrates of PNGase in the eggs and the embryos of this fish and are the origin of the free glycan chains. Based on these findings, we proposed the significance of de-N-glycosylation catalyzed by PNGase as a basic protein re-modification process that regulates the function of certain glycoproteins in animal cells. Less
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