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Cytoskeletal studies of peculiar mitoses during male gametogenesis of angiosperms using immunofluorescence methods.

使用免疫荧光方法对被子植物雄性配子发生过程中特殊有丝分裂进行细胞骨架研究。

基本信息

批准号：
01540583
负责人：
TERASAKA Osamu
金额：
$ 1.02万
依托单位：
Jikei University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

During the male gametogenesis of anglospenns, some peculiar events concerning cell division and differentiation successively occur ; nuclear migration in microspore cell, unequal division of microspore, differentiation between generative and vegetative cells and generative cell division in pollen tube. The associations of microtubules (Ws), actin and myosin with these events were studied using immlmofluo-rescence methods and inhibitory experiments. In Tradescantia paludosa, microspore nuclei migrated twice before the division. The second nuclear migration, essential to the unequal division, was dependent on Nffs, but the first was independent. MTs constructed asymmetric mitotic spindle and phragmoplast in microspore division. MTs mediated generative cell elongation but not pollen tube elongation. The spindles in generative cell divisions of Calanthe and some other species were peculiar configurations in which metaphase chromosomes lay in tandem along the spindle axis and sister chromos … More omes separated anti-parallelly by spindle elongation during anaphase. No F-actin associating with the nuclear migrations or unequal division was found in microspores. Distinct F-actin was found only in the phragmoplast. F-actin was organized on both transverse sides of the vegetative nucleus after microspore division, and developed into an abundant complex network in mature pollen grains. This F-actin played an important role in pollen tube growth or cytoplasmic streaming, but not in generative cell division. In conclusion, the different dynamics between MTs and actin during male gametogenesis were examined. Myosin was detected on the surface of generative cells and vegetative cell organelles of T. virginiana and two other species. The migration of these and of vegetative nuclei within pollen tubes, as well as tube growth, were inhibited by N-ethylmaleimide, an inhibitor of actomyosin ATPase activity. Indications were that the force for their migration was produced by an actomyosin system, although further research is underway on the subject of whether or not myosin is present in vegetative nuclei. Less

在雄花的雄配子体发生过程中，相继发生了一些与细胞分裂和分化有关的特殊事件；小孢子细胞的核迁移，小孢子的不均匀分裂，生殖细胞和营养细胞的分化以及花粉管中生殖细胞的分裂。用免疫荧光法和抑制实验研究了微管、肌动蛋白和肌球蛋白与这些事件的关联。小孢子核在分裂前有2次迁移。第二次核心移民是对不平等分配至关重要的，它依赖于Nffs，但第一次是独立的。mt在小孢子分裂中形成不对称的纺锤体和层质体。mt介导生殖细胞伸长，但不介导花粉管伸长。Calanthe和其他一些物种生殖细胞分裂的纺锤体是中期染色体沿纺锤体轴和姐妹染色体串联排列的特殊构型，后期纺锤体伸长导致更多的染色体反平行分离。在小孢子中未发现与核迁移或不均匀分裂有关的f -肌动蛋白。明显的f -肌动蛋白仅在膜质体中发现。小孢子分裂后，f -肌动蛋白分布在营养核的两侧，在成熟花粉粒中形成丰富的复杂网络。这种f -肌动蛋白在花粉管生长或细胞质流动中起重要作用，但在生殖细胞分裂中不起作用。研究了MTs和肌动蛋白在雄性配子体发生过程中的不同动态。在弗吉尼亚田鼠和其他两种植物的生殖细胞和营养细胞器表面检测到肌球蛋白。n -乙基马来酰亚胺（n -乙基马来酰亚胺是一种肌动球蛋白atp酶活性抑制剂）抑制了花粉管内营养细胞核的迁移和花粉管的生长。有迹象表明，它们迁移的力量是由肌动球蛋白系统产生的，尽管关于肌动球蛋白是否存在于营养细胞核的问题还在进一步研究中。少