Mironova A A, Barykina N V, Zatsepina O V
Tsitologiia. 2014;56(7):489-99.
The organization and functional activity of the nucleoli of mammalian cells can be modified in response to various stress factors. However, data on the reaction of nucleoli to oxidative stress remain limited. In this paper, we have studied the localization of nucleolar RNAs and two RNA-binding proteins--fibrillarin, a pre-rRNA processing factor, and nucleophosmin/B23, a pre-ribosome assembly factor, in HeLa cells exposed to 1 mM H2O2 up to four hours. We have shown that under the conditions used H2O2 does not induce death, but inhibits rDNA transcription, reduces the total RNA content in the cells and the amount of 18S rRNA in the nucleoli, and causes relocalization of fibrillarin and nucleophosmin/B23 to the nucleoplasm. To date, similar changes in the localization of fibrillarin were described in mammalian cells only after HgCl2 treatment. Redistribution of nucleophosmin/B23 observed in H2O2-treated cells occurred in mammalian cells under inhibition of rDNA transcription and early rRNA processing. Overall, this study shows the high sensitivity of the nucleoli of HeLa cells to acute oxidative stress, which is clearly evident on the cytological level.
哺乳动物细胞中核仁的组织和功能活性可因各种应激因素而发生改变。然而，关于核仁对氧化应激反应的数据仍然有限。在本文中，我们研究了核仁RNA以及两种RNA结合蛋白——原核糖体RNA加工因子纤维蛋白原和核糖体前体组装因子核磷蛋白/B23，在暴露于1 mM过氧化氢长达4小时的HeLa细胞中的定位。我们发现，在所使用的条件下，过氧化氢不会诱导细胞死亡，但会抑制核糖体DNA转录，降低细胞中的总RNA含量以及核仁中18S核糖体RNA的量，并导致纤维蛋白原和核磷蛋白/B23重新定位到核质中。迄今为止，仅在氯化汞处理后的哺乳动物细胞中描述过纤维蛋白原定位的类似变化。在过氧化氢处理的细胞中观察到的核磷蛋白/B23的重新分布，发生在核糖体DNA转录和早期核糖体RNA加工受到抑制的哺乳动物细胞中。总体而言，这项研究表明HeLa细胞核仁对急性氧化应激具有高度敏感性，这在细胞学水平上清晰可见。
