Epigenetic Changes are Associated with Programmed Cell Death Induced by Heat Stress in Seedling Leaves of Zea mays.
Epigenetic Changes are Associated with Programmed Cell Death Induced by Heat Stress in Seedling Leaves of Zea mays.
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DOI：
10.1093/pcp/pcv023
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发表时间：
2015-05
影响因子：
4.9
通讯作者：
Pu Wang;Lin Zhao;Haoli Hou;Hao Zhang;Y. Huang;Yapei Wang;Hui Li;Fei Gao;Shihan Yan;Lijia Li
中科院分区：
文献类型：
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作者：
Pu Wang;Lin Zhao;Haoli Hou;Hao Zhang;Y. Huang;Yapei Wang;Hui Li;Fei Gao;Shihan Yan;Lijia Li
组蛋白修饰在染色质结构和功能的调节中发挥着至关重要的作用，以应对不利的外部刺激。然而，人们对表观遗传修饰与响应环境压力的程序性细胞死亡（PCD）之间可能存在的关系知之甚少。在这里，我们发现热应激在玉米幼苗叶片中诱导 PCD，其特征是通过末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记 (TUNEL) 测试检测到染色质 DNA 梯状和 DNA 链断裂。在热处理的幼苗中，活性氧（ROS）相关酶超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性随着时间的推移逐渐增加。然而，H2O2 的浓度仍保持在相对较低的水平，而超氧阴离子（[式：见正文]）的浓度则有所增加，伴随着热处理后出现较高的离子泄漏率。与对照幼苗相比，经热胁迫处理的幼苗叶片中组蛋白 H3K9、H4K5 和 H3 的总乙酰化水平显着升高，而组蛋白 H3K4 二甲基化水平没有变化，组蛋白 H3K9 二甲基化水平降低，并伴有表明染色质脱聚的核仁大小增加。此外，用曲古抑菌素 A (TSA) 处理幼苗总是会导致基因组组蛋白过度乙酰化，从而导致细胞内 [公式：见正文] 水平增加。结果表明，热应激持续诱导[公式：见正文]，导致 PCD 与玉米叶片中组蛋白修饰变化有关。
Histone modification plays a crucial role in regulation of chromatin architecture and function, responding to adverse external stimuli. However, little is known about a possible relationship between epigenetic modification and programmed cell death (PCD) in response to environmental stress. Here, we found that heat stress induced PCD in maize seedling leaves which was characterized by chromatin DNA laddering and DNA strand breaks detected by a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) test. The activities of the reactive oxygen species (ROS)-related enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were progressively increased over time in the heat-treated seedlings. However, the concentration of H2O2 remained at relatively lower levels, while the concentration of superoxide anion ([Formula: see text]) was increased, accompanied by the occurrence of higher ion leakage rates after heat treatment. The total acetylation levels of histones H3K9, H4K5 and H3 were significantly increased, whereas the di-methylation level of histone H3K4 was unchanged and the di-methylation level of histone H3K9 was decreased in the seedling leaves exposed to heat stress compared with the control seedlings, accompanied by increased nucleolus size indicative of chromatin decondensation. Furthermore, treatment of seedlings with trichostatin A (TSA), which always results in genomic histone hyperacetylation, caused an increase in the [Formula: see text] level within the cells. The results suggested that heat stress persistently induced [Formula: see text], leading to PCD in association with histone modification changes in the maize leaves.