Sharma Santosh Kumar, Yamamoto Maki, Mukai Yasuhiko
Laboratory of Plant Molecular Genetics, Division of Natural Sciences, Osaka Kyoiku University, Kashiwara, Osaka, 582-8582, Japan.
Department of Rehabilitation Sciences, Kansai University of Welfare Sciences, Kashiwara, Osaka, Japan.
Protoplasma. 2017 Jan;254(1):161-165. doi: 10.1007/s00709-015-0925-z. Epub 2016 Jan 15.
Pollen developmental pathway in plants involving synchronized transferal of cellular divisions from meiosis (microsporogenesis) to mitosis (pollen mitosis I/II) eventually offers a unique "meiosis-mitosis shift" at pollen mitosis I. Since the cell type (haploid microspore) and fate of pollen mitosis I differ from typical mitosis (in meristem cells), it is immensely important to analyze the chromosomal distribution of phosphorylated H3S10 histone during atypical pollen mitosis I to comprehend the role of histone phosphorylation in pollen development. We investigated the chromosomal phosphorylation of H3S10 histone during pollen mitosis I in orchids using immunostaining technique. The chromosomal distribution of H3S10ph during pollen mitosis I revealed differential pattern than that of typical mitosis in plants, however, eventually following the similar trends of mitosis in animals where H3S10 phosphorylation begins in the pericentromeric regions first, later extending to the whole chromosomes, and finally declining at anaphase/early cytokinesis (differentiation of vegetative and generative cells). The study suggests that the chromosomal distribution of H3S10ph during cell division is not universal and can be altered between different cell types encoded for diverse cellular processes. During pollen development, phosphorylation of histone might play a critical role in chromosome condensation events throughout pollen mitosis I in plants.
植物中的花粉发育途径涉及细胞分裂从减数分裂（小孢子发生）到有丝分裂（花粉有丝分裂I/II）的同步转移，最终在花粉有丝分裂I时产生独特的“减数分裂-有丝分裂转变”。由于花粉有丝分裂I的细胞类型（单倍体小孢子）和命运与典型的有丝分裂（分生组织细胞中的有丝分裂）不同，因此分析非典型花粉有丝分裂I期间磷酸化H3S10组蛋白的染色体分布对于理解组蛋白磷酸化在花粉发育中的作用极为重要。我们使用免疫染色技术研究了兰花花粉有丝分裂I期间H3S10组蛋白的染色体磷酸化情况。花粉有丝分裂I期间H3S10ph的染色体分布显示出与植物典型有丝分裂不同的模式，然而，最终遵循了动物有丝分裂的类似趋势，即H3S10磷酸化首先在着丝粒周围区域开始，随后扩展到整个染色体，最后在后期/早期胞质分裂（营养细胞和生殖细胞分化）时下降。该研究表明，细胞分裂期间H3S10ph的染色体分布并非普遍存在，并且在编码不同细胞过程的不同细胞类型之间可能会发生改变。在花粉发育过程中，组蛋白磷酸化可能在植物整个花粉有丝分裂I的染色体浓缩事件中起关键作用。
