Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100, Toruń, Poland.
Planta. 2012 Jul;236(1):171-84. doi: 10.1007/s00425-012-1618-x. Epub 2012 Mar 8.
The nucleolar activity of Hyacinthus orientalis L. embryo sac cells was investigated. The distributions of nascent pre-rRNA (ITS1), 26S rRNA and of the 5S rRNA and U3 snoRNA were determined using fluorescence in situ hybridization (FISH). Our results indicated the different rRNA metabolism of the H. orientalis female gametophyte cells before and after fertilization. In the target cells for the male gamete, i.e., the egg cell and the central cell whose activity is silenced in the mature embryo sac (Pięciński et al. in Sex Plant Reprod 21:247-257, 2008; Niedojadło et al. in Planta doi: 10.1007/s00425-012-1599-9 , 2011), rRNA metabolism is directed at the accumulation of rRNPs in the cytoplasm and immature transcripts in the nucleolus. In both cells, fertilization initiates the maturation of the maternal pre-rRNA and the expression of zygotic rDNA. The resumption of rRNA transcription observed in the hyacinth zygote indicates that in plants, there is a different mechanism for the regulation of RNA Pol I activity than in animals. In synergids and antipodal cells, which have somatic functions, the nucleolar activity is correlated with the metabolic activity of these cells and changes in successive stages of embryo sac development.
研究了风信子胚囊细胞的核仁活性。使用荧光原位杂交（FISH）技术确定了新生前 rRNA（ITS1）、26S rRNA 和 5S rRNA 和 U3 snoRNA 的分布。我们的结果表明，在受精前后，风信子雌性配子体细胞的 rRNA 代谢存在差异。在雄性配子的靶细胞中，即卵细胞和中央细胞，其在成熟胚囊中活性被沉默（Pięciński 等人，Sex Plant Reprod 21:247-257, 2008；Niedojadło 等人，Planta doi: 10.1007/s00425-012-1599-9, 2011），rRNA 代谢的方向是在细胞质中积累 rRNPs 和不成熟的核仁内转录物。在这两个细胞中，受精启动了母体前 rRNA 的成熟和合子 rDNA 的表达。在风信子合子中观察到的 rRNA 转录的恢复表明，在植物中，RNA Pol I 活性的调节机制与动物不同。在具有体细胞功能的助细胞和反足细胞中，核仁活性与这些细胞的代谢活性以及胚囊发育的连续阶段的变化相关。
