Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Research Institution||Tokyo Institute of Technology|
HOSHI Motonori Department of Life Science, Tokyo Institute of Technology, 生命理工学部, 教授 (20012411)
MARINO Rita Department of Cell and Developmental Biology, Stazione Zoologica 'Anton Dohrn', 研究員
PINTO M.ROSA 国立酵素, タンパク質化学研究所, 研究員
DALE Brian Department of Cell and Developmental Biology, Stazione Zoologica 'Anton Dohrn', 主任研究員
DE Santis RO 国立ナポリ臨海実験所, 部長
USUI Noriko Department of Anatomy, Teikyo University School of Medicine, 医学部, 助教授 (50082136)
CHIDA Kazuyoshi Department of Life Science, Tokyo Institute of Technology, 生命理工学部, 助手 (70222130)
MATSUMOTO Midori Department of Life Science, Tokyo Institute of Technology, 生命理工学部, 助手 (00211574)
NISHIDA Hiroki Department of Life Science, Tokyo Institute of Technology, 生命理工学部, 助教授 (60192689)
ROSARIA Pinto M. Institute of Protein Biochemistry and Enzymology, C.N.R.
SANTIS Rosaria De Department of Cell and Developmental Biology, Stazione Zoologica 'Anton Dohrn'
MARINO Rita 国立ナポリ臨海実験所, 細胞発生学部, 研究員
PINTO Rosari 国立酵素, タンパク質化学研究所, 研究員
DALE Brian 国立ナポリ臨海実験所, 細胞発生学部, 主任研究員
DE Santis Ro 国立ナポリ臨海実験所, 細胞発生学部, 部長
PINTO M.Rosa 国立酵素タンパク質化学研究所, 研究員
DESANTIS Ros 国立ナポリ臨海実験所, 部長
|Project Period (FY)
1990 – 1992
Completed(Fiscal Year 1992)
|Budget Amount *help
¥10,300,000 (Direct Cost : ¥10,300,000)
Fiscal Year 1992 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1991 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1990 : ¥3,300,000 (Direct Cost : ¥3,300,000)
|Keywords||Ascidians / sperm-egg interactions / self-sterility / membrane fusion / lysin / protease / glycosidase / glycoprotein / 濾胞細胞 / プロテア-ゼ / αーLーフコシダ-ゼ / rDNA / αーLーフコシダ-|
The ascidians are hermaphrodite and many species are seif-sterile. Using two species of self-sterile solitary ascidiansas model systems, Ciona intestinalis (Enterogona) and Halocynthia roretzi (Pleurogona), molecular mechanisms underlying the sperm-egg interactions were studied.
We postulated previously that a sperm glycosidase (e.g., alpha-L-fucosidase in Ciona) and corresponding sugar chains of the vitelling coat (VC) mediate the binding of ascidian sperm to the homologous VC. Several lines of experimental evidence has further supported this hypothesis in both Ciona and Halocynthia. In H. roretzi, we have purified the major VC glycoprotein of about 70 kDa. It has terminal fucose residues and presumably serves as a sperm-receptor. Its amino acid sequence was partially revealed.
A chymotrypsin-like protease was purified from Ciona sperm as a VC-lysin and proved to digest the outermost thin layer of the VC. It was also shown that a Zn^<++>-dependent metalloprotease is involved in sperm-eg
g fusion in Ciona.
By using in vitro fertilization assay of oocytes from Ciona ovaries, we have found that self-sterility is controlled by products, presumably a glycoprotein, of the overlying follicle cells. When fully-grown ovarian oocytes with a germinal vesicle were incubated in sea water at room temperature, they underwent germinal vesicle breakdown within 20 minutes and became fertile, and eventually acquired self-sterility within a maximum of 3 hours of incubation. When they were deprived of follicle cells by gentle shaking before incubation, most of them remained self-fertile even after 3 hours. If follicle cell-free oocytes were incubated with the free follicle cells, they became self-sterile as well as follicle cell-intact oocytes.
The acquisition of self-sterility was accompanied by an ultrastructural change in the VC fixed with tannic acid : an electron-dense, thin layer appeared on the outer surface of the VC after 3 hours of incubation. This was the layer digested by the chymotryptic lysin in the sperm. Therefore it is suggested that the induction of acrosome reaction is the site modulated by allo-recognition between sperm and VC. Less