| Project/Area Number |
63540576
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Kochi University |
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Principal Investigator |
KAWAMURA Kazuo (1989-1990) Kochi Univ., Fac. of Sci., Dept. of Biol., Associate Professor., 理学部, 助教授 (30136361)
中内 光昭 (1988) 高知大学, 理学部, 教授 (00036526)
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| Co-Investigator(Kenkyū-buntansha) |
川村 和夫 高知大学, 理学部, 助教授 (30136361)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Ascidian / Budding / Organization center / Stem cell / Animal lectin / Exocytosis / Cell proliferation / Prostaglandins / 上皮転換 / ガラクト-ス含有糖蛋白質 / 細胞外マトリックス / アラキドン酸カスケ-ド / プロスタグランディン / 形態形成 / 個体性 |
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| Research Abstract |
In earlier works of this project, I found that the gut domain is an organization center for antero-posterior pattern formation of a palleal bud in polystyelid ascidians such as Polyzoa and Polyandrocarpa. The organization center was characterized by the aggregation and epithe ial transformation of totipotent stem cells, hemoblasts, and by their entrance into quick cell cycling (Tc=12.5hr). Recently, we have purified a calcium-dependent galactosebinding 14kDa lectin (TC-14) from P. misakiensis, and determined its amino acid sequence. The lectin labeled with FITC or biotin stained hemoblasts. Anti TC-14 polyclonal antibody reacted with the extracellular matrix (ECM) that appeared in the organization center at the earliest stage of bud development. It blocked hemoblasts to differentiate into the gastric epithelium. The results strongly suggested that lectin-positive ECM plays a role in aggregation of hemoblasts toward the epithelium. After western blotting of Polyandrocarpa crude extracts
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on SDS-PAGE, TC-14 showed an affinity for 20kDa polypeptide that was a subunit of 64kDa glycoprotein (GP-64). This reaction required Ca^<2+>, showing that GP-64 is an in vivo target molecule of TC-14. TC-14 had a growthinhibitory effect on hemoblasts in in vivo and in vitro bioassays, whereas GP-64 enhanced their in vivtro proliferation rem arkably. These results strongly suggested that molecular interactions between TC-14 and GP-64 play a key role in totipotency, cell growth and epithelial transformation of hemoblasts at the organization center.
I also studied non-peptide effector molecules, of which Prostaglandins (PGs) were found to be involved in exocytosis of lectin granules included in epithelial cells. PGH synthetase was found serologically in blood cells in the vicinity of organization center. Indomethacin, a specific inhibitor of PGs biosynthesis, blocked the exocytosis of lectin granules. The effect of indomethacin was canceled in part by PGs and the organization center reappeared. It is concluded that the determination of organization center in palleal buds involves the spatio-temporal integration of exocytosis of various functional molecules such as TC-14 and GP-64. Less
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