Molecular mechanisms underlying self-sterility in the ascidians

海鞘自体不育的分子机制

• 批准号: 06454685
• 负责人: HOSHI Motonori
• 金额: $ 3.84万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06454685/
• 关键词: allo-recognition; sperm-egg-binding; contact-reaction; hemocyte; glycoprotein; Ascidian; alpha-L-Fucosidase; Metalloendoprotease; アロ認識; 精子結合; キメラ胚; フェノールオキシダーゼ

Little is so far known on the molecular mechanisms underlying self-sterility in the ascidian gametes, a typical example of the allogeneic recognition. However, an allogeneic interaction named "contact reaction" is well established in the hemocytes of the ascidian, Halocynthia roretzi. On an assumption that allo-recognition molecules in gametes and those in hemocytes are the same or closely related, we searched for such molecules in the gametes and hemocytes of the ascidian. Major findings in this project are itemized as follows.1) Vacuolate cells secreted phenol oxidase upon contact reaction, which allowed us to develop a quantitative assay for the contact reaction.2) Vacuolated cells expressed an allo-molecule (s) and its receptor, whereas granular cells did not express such a molecule in a way to be recognized by vacuolated cells.3) Follicle cells attaching to the vitelline coat expressed an allo-molecule (s).4) cDNA of sperm alpha-L-fucosidase that mediates sperm binding to the vitelline coat was cloned and partially sequenced.5) A putative sperm-receptor glycoprotein of 70 kDa was isolated from the vitelline coat and partially sequenced.6) The gametes became self-fertile in high Mg^<2+>-or caffeine-seawater.

海鞘配子自身不育是异源识别的一个典型例子，但其分子机制至今仍知之甚少。然而，一种名为“接触反应”的同种异体相互作用在海鞘，Halocynthia roretzi的血细胞中得到了很好的建立。假设配子和血细胞中的同种异体识别分子是相同或密切相关的，我们在海鞘的配子和血细胞中寻找这样的分子。本研究的主要发现如下：1）接触反应时，细胞分泌酚氧化酶，这使我们能够建立接触反应的定量测定方法。2）接触细胞表达一种异源分子及其受体，而颗粒细胞不表达这种分子，这种分子不能被空泡化细胞识别。4）克隆了介导精子与卵黄膜结合的精子α-L-岩藻糖苷酶的cDNA并进行了部分测序; 5）从卵黄膜中分离了一个70 kDa的假定精子受体糖蛋白并进行了部分测序; 6）配子在高Mg^<2+>-或咖啡因-海水中可自花受精。

项目成果

A. Ushiyama, A. Shima and M. Hoshi: "Estimation by radiation inactivation of the minimum functional size of acrosome reaction-inducing substance (ARIS) in the starfish, Asterias amurensis" Zygote. 3(in press). (1995)

A. Ushiyama、A. Shima 和 M. Hoshi：“通过辐射灭活估计海星 Asterias amurensis 中顶体反应诱导物质 (ARIS) 的最小功能大小”合子。

M. Hoshi: "Glycosidases, Proteases and Ascidian Fertilization" Seminars Dev. Biol.5. 201-208 (1994)

M. Hoshi：“糖苷酶、蛋白酶和海鞘施肥”研讨会开发。

M.Hoshi: Allogeneic recognition in ascidian fertilization. In Sixth Lake Shirakaba Placenta Conference 1994 Biology of Pregnancy ed.T.Nakayama and T.Makino, Keiseisha, Tokyo, 60-65 (1995)

M.Hoshi：海鞘受精中的同种异体识别。

K. Chiba: "A Periodic Network of G Protein βγ Subunit Coexisting with Cytokeratin Filament in Starfish Oocytes" Dev. Biol. in press.

K. Chiba：“海星卵母细胞中与细胞角蛋白丝共存的 G 蛋白 βγ 亚基的周期性网络”Dev Biol。

M.Hoshi: "In Sixth Lake Shirakaba Placents Conference 1994 Biology of Pregnancy" ed.T.Nakayama and T.Makino,pp.60-65,Keiseisha,Tokyo, 106 (1995)

M.Hoshi：“1994 年第六届白桦湖胎盘会议中的妊娠生物学”ed.T.Nakayama 和 T.Makino，第 60-65 页，Keiseisha，东京，106 (1995)