Immunological analysis of chromatin differentiation in higher plant cells

在本研究中，我们利用特定的抗血清，在长花百合的雄配子核(生殖核和精子核)的碱性蛋白中，检测到了三种在小孢子发生和花粉发育过程中具有特定时空分布的组蛋白变体。一种是减数分裂的组蛋白(MHL)，据报道是一种类似hl的组蛋白。它在小孢子母细胞减数分裂之前出现，在小孢子发生和大孢子发生过程中优先定位于着丝粒/着丝点。使用该抗血清，我们能够观察到同源染色体着丝粒在前期的融合和分离，在后期姐妹着丝粒的不分离，在后期的分离，以及着丝粒与纺锤体微管的附着。第二类是组蛋白h1，它也是组蛋白h1的变体。它不是配子发生特有的蛋白，但在雄配子核中大量积累。类似的蛋白质存在于高等植物细胞的核仁中，包括单子叶和双子叶植物，以及百合的体细胞和早期生殖细胞的核仁中。最后是雄性配子特有的核心组蛋白变体，命名为gH2A、gH2B和GH3。它们出现在小孢子有丝分裂后的双细胞花粉发育过程中，并特异地定位于生殖核和精子核。但是，它们针对的是体细胞中的核仁。由此推测，这些组蛋白变体与特定的染色质组织密切相关，雄配子核的染色质组织与核仁的染色质组织相似。

In this study, using specific antisera, we have detected three kinds of histone variant, that shows specific temporal and spatial distribution during microsporogenesis and pollen development, among basic proteins included in male gametic (generative and sperm) nuclei of Lilium longiflorum. One is a meiotic histone (mHl), which had been reported to be a histone Hl-like protein. It appears preceding meiotic division in microsporocytes and is preferentially localized on the centromeres/kinetochores during microsporogenesis and megasporogenesis. Using this antiserum, we were able to visualize the fusion and disjunction of centromeres of homologous chromosomes in prophase I, nonseparation of the sister centromeres at anaphase,, separation of them at anaphase II and the attachment of the centromeres to spindle microtubules. Second group is a gHl, which is also a variant of histone Hl. It is not a gametogenesis-specific protein, but abundantly accumulates in the male gametic nuclei. The analogous proteins are present in nucleoli of higher plant cells including monocotyledon and dicotyledon as well as in nucleoli of somatic and early reproductive cells of this lily. Last are male gamete-specific, core histone variants, that were designated gH2A, gH2B and gH3. They appear during the development of bicellular pollen after microspore mitosis and are specifically localized in the generative and sperm nuclei. But, they were targeted to the nucleoli in somatic cells. From these observations, it is assumed that these histone variants are closely related to specific chromatin organization and the chromatin organization of the male gametic nuclei is similar to that of nucleolus.