Characteristics and Regulation of Meiosis

减数分裂的特征和调控

• 批准号: 07283102
• 负责人: YAMAMOTO Masayuki
• 金额: $ 198.53万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-07283102/
• 关键词: meiosis; fission yeast; budding yeast; neinatode; Xenopus; oocye maturarion; Mos; RNA; ヒトデ; MAPキナーゼ; meiRNA; 微小管結合蛋白質; MPF; RNA結合蛋白質; 細胞分裂周期; 無細胞系; cdc2キナーゼ

Major results obtained in this research project are following : 1. In fission yeast, dephosphorylation of the key meiotic regulator Mei2 commits cells to meiosis. Mei2 is an RNA-binding protein, and cooperates with meiRNA to promote the first meiotic division. The essential role of meiRNA for meiosis is to assist transport of Mei2 from cytoplasm to nucleus. 2. Precise analysis of Xenopus oocyte maturation has led to three conclusions which decline previous suppositions. (1) A decrease in the activity of PKA is not mandatory for the onset of oocyte maturation. (2) cdc2 kinase is not involved in activation of the CSF activity of Mos. (3) The content of nuclei influences progression of oocyte maturation. 3. A homologue of Mos has been cloned from starfish, indicating that Mos is not restricted to vertebrates, in which oocytes arrest at the second meiotic division during maturation. This suggests that a general function of Mos is to suppress an outbreak of mitotic cell cycle progression after the first meiotic division. 4. A nuclear export signal (NES) has been found in cyclin B, which regulates meiotic M phase. Nuclear export of cyclin B is thought to be important for the DNA-damage checkpoint control. 5. In budding yeast, proteins Mrel 1, Rad50 and Xrs2 are required for two steps in meiotic recombination, i.e., they are involved in the formation of a double strand break at the recombination hot spot and in the subsequent digestion of the generated termini. Interestingly, these proteins form different complexes to fulfill each of these two functions. 6. In nematode, the daz-1 gene encoding an RNA-binding protein has been found to be essential for meiotic progression in oogenesis but not in spermatogenesis. Worms defective in daz-1 arrest female meiosis at the pachytene.

本研究项目取得的主要成果如下： 1. 在裂殖酵母中，减数分裂关键调节因子 Mei2 的去磷酸化使细胞进行减数分裂。 Mei2是一种RNA结合蛋白，与meiRNA协同促进第一次减数分裂。 meiRNA 在减数分裂中的重要作用是协助 Mei2 从细胞质转运至细胞核。 2. 对爪蟾卵母细胞成熟的精确分析得出了三个结论，推翻了先前的假设。 (1) PKA 活性的降低对于卵母细胞成熟的开始并不是强制性的。 (2)cdc2激酶不参与Mos的CSF活性的激活。 (3)细胞核含量影响卵母细胞的成熟进程。 3. Mos的同源物已从海星中克隆出来，表明Mos并不局限于脊椎动物，在脊椎动物中，卵母细胞在成熟过程中停滞在第二次减数分裂。这表明Mos的一般功能是抑制第一次减数分裂后有丝分裂细胞周期进程的爆发。 4. 在调节减数分裂M期的细胞周期蛋白B中发现核输出信号(NES)。细胞周期蛋白 B 的核输出被认为对于 DNA 损伤检查点控制很重要。 5. 在芽殖酵母中，减数分裂重组的两个步骤需要蛋白质 Mrel 1、Rad50 和 Xrs2，即它们参与重组热点处双链断裂的形成以及随后对所生成末端的消化。有趣的是，这些蛋白质形成不同的复合物来实现这两种功能。 6. 在线虫中，已发现编码 RNA 结合蛋白的 daz-1 基因对于卵子发生的减数分裂进程至关重要，但对于精子发生则不然。 daz-1 有缺陷的线虫会在粗线期阻止雌性减数分裂。

项目成果

Watanabe, Y., Shinozaki-Yabana, S., Chikashige, Y., Hiraoka, Y. and Yamamoto, M.: "Phosphorylation of RNA-binding protein controls cell cycle switch from mitotic to meiotic in fission yeast"Nature. 386. 187-190 (1997)

Watanabe, Y.、Shinozaki-Yabana, S.、Chikashige, Y.、Hiraoka, Y. 和 Yamamoto, M.：“RNA 结合蛋白的磷酸化控制裂殖酵母中细胞周期从有丝分裂到减数分裂的转换”《自然》。

Yamashita,A.: "Microtubule-associated coiled-coil protein Ssm4 is involved in the meiotic development in fission yeast." Genes to Cells. 2. 155-166 (1997)

Yamashita,A.：“微管相关卷曲螺旋蛋白 Ssm4 参与裂殖酵母的减数分裂发育。”

Takenaka,K.: "MAP kinase is required for the spindle assembly checkpoint but is dispensable for the normal M phase entry and exit in Xenopus egg cell cycle extract." Journal of Cell Biology. 136. 1091-1097 (1997)

Takenaka,K.：“MAP 激酶是纺锤体组装检查点所必需的，但对于非洲爪蟾卵细胞周期提取物中正常的 M 期进入和退出来说是可有可无的。”

Okumura, E., Sekiai, T., Hisanaga, S., Tachibana, K. and Kishimoto, T.: "Initial triggering of M-phase in starfish oocytes : A possible novel component of MPF besides cdc2 kinase"Journal of Cell Biology. 132. 125-135 (1996)

Okumura, E.、Sekiai, T.、Hisanaga, S.、Tachibana, K. 和 Kishimoto, T.：“海星卵母细胞中 M 期的初始触发：除 cdc2 激酶之外的 MPF 的可能新成分”细胞生物学杂志

Tachibana,K.: "MAP kinase links the fertilization signal transduction pathway to the G1/S-phase transition in starfish eggs." EMBO Journal. 16. 4333-4339 (1997)

Tachibana,K.：“MAP 激酶将受精信号转导途径与海星卵的 G1/S 相转变联系起来。”