Novikova Galina V, Mur Luis A J, Nosov Alexander V, Fomenkov Artem A, Mironov Kirill S, Mamaeva Anna S, Shilov Evgeny S, Rakitin Victor Y, Hall Michael A
Laboratory of Intracellular Regulation, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences Moscow, Russia.
Molecular Plant Pathology Group, Institute of Biological, Environmental and Rural Sciences, Aberystwyth University Aberystwyth, UK.
Front Physiol. 2017 Mar 10;8:142. doi: 10.3389/fphys.2017.00142. eCollection 2017.
Ethylene is known to influence the cell cycle (CC) via poorly characterized roles whilst nitric oxide (NO) has well-established roles in the animal CC but analogous role(s) have not been reported for plants. As NO and ethylene signaling events often interact we examined their role in CC in cultured cells derived from wild-type (Col-0) plants and from ethylene-insensitive mutant plants. Both NO and ethylene were produced mainly during the first 5 days of the sub-cultivation period corresponding to the period of active cell division. However, in cells, ethylene generation was significantly reduced while NO levels were increased. With application of a range of concentrations of the NO donor, sodium nitroprusside (SNP) (between 20 and 500 μM) ethylene production was significantly diminished in Col-0 but unchanged in cells. Flow cytometry assays showed that in Col-0 cells treatments with 5 and 10 μM SNP concentrations led to an increase in S-phase cell number indicating the stimulation of G1/S transition. However, at ≥20 μM SNP CC progression was restrained at G1/S transition. In the mutant strain, the index of S-phase cells was not altered at 5-10 μM SNP but decreased dramatically at higher SNP concentrations. Concomitantly, 5 μM SNP induced transcription of genes encoding and in Col-0 cells whereas transcription of s and s were not significantly altered in cells at any SNP concentrations examined. Hence, it is appears that EIN2 is required for full responses at each SNP concentration. In cells, greater amounts of NO, reactive oxygen species, and the tyrosine-nitrating peroxynitrite radical were detected, possibly indicating NO-dependent post-translational protein modifications which could stop CC. Thus, we suggest that in cultured cells NO affects CC progression as a concentration-dependent modulator with a dependency on EIN2 for both ethylene production and a NO/ethylene regulatory function.
已知乙烯通过尚不明确的作用影响细胞周期（CC），而一氧化氮（NO）在动物细胞周期中具有明确的作用，但在植物中尚未报道类似作用。由于NO和乙烯信号事件经常相互作用，我们研究了它们在源自野生型（Col-0）植物和乙烯不敏感突变体植物的培养细胞的细胞周期中的作用。NO和乙烯主要在继代培养期的前5天产生，这与活跃细胞分裂期相对应。然而，在突变体细胞中，乙烯生成显著减少，而NO水平增加。应用一系列浓度的NO供体硝普钠（SNP）（20至500μM）后，Col-0细胞中的乙烯生成显著减少，而突变体细胞中则无变化。流式细胞术分析表明，在Col-0细胞中，用5和10μM SNP浓度处理导致S期细胞数量增加，表明G1/S期转换受到刺激。然而，当SNP浓度≥20μM时，细胞周期进程在G1/S期转换处受到抑制。在突变体菌株中，5-10μM SNP时S期细胞指数未改变，但在较高SNP浓度下显著降低。同时，5μM SNP诱导Col-0细胞中编码[具体基因1]和[具体基因2]的基因转录，而在任何检测的SNP浓度下，突变体细胞中[具体基因3]和[具体基因4]的转录均未显著改变。因此，似乎EIN2是在每个SNP浓度下产生完全反应所必需的。在突变体细胞中，检测到更多的NO、活性氧和酪氨酸硝化的过氧亚硝酸盐自由基，这可能表明NO依赖性的翻译后蛋白质修饰，从而可能阻止细胞周期。因此，我们认为在突变体培养细胞中，NO作为浓度依赖性调节剂影响细胞周期进程，并且在乙烯生成以及NO/乙烯调节功能方面依赖于EIN2。
