Borg Michael, Berger Frédéric
Gregor Mendel Institute, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
Plant J. 2015 Jul;83(1):177-88. doi: 10.1111/tpj.12856. Epub 2015 May 21.
The plant life cycle alternates between a diploid sporophytic phase and haploid gametophytic phase, with the latter giving rise to the gametes. Male gametophyte development encompasses two mitotic divisions that results in a simple three-celled structure knows as the pollen grain, in which two sperm cells are encased within a larger vegetative cell. Both cell types exhibit a very different type of chromatin organization - highly condensed in sperm cell nuclei and highly diffuse in the vegetative cell. Distinct classes of histone variants have dynamic and differential expression in the two cell lineages of the male gametophyte. Here we review how the dynamics of histone variants are linked to reprogramming of chromatin activities in the male gametophyte, compaction of the sperm cell genome and zygotic transitions post-fertilization.
植物生命周期在二倍体孢子体阶段和单倍体配子体阶段之间交替，后者产生配子。雄配子体发育包括两次有丝分裂，产生一个简单的三细胞结构，即花粉粒，其中两个精细胞包裹在一个较大的营养细胞内。两种细胞类型表现出非常不同的染色质组织类型——在精细胞核中高度浓缩，在营养细胞中高度分散。不同类别的组蛋白变体在雄配子体的两个细胞谱系中具有动态和差异表达。在这里，我们综述了组蛋白变体的动态如何与雄配子体中染色质活性的重编程、精细胞基因组的压缩以及受精后的合子转变相关联。
