Leaf tructural characteristics are less important than leaf chemical properties in determining the response of leaf mass per area and photosynthesis of Eucalyptus saligna to industrial-age changes in [ CO 2 ] and temperature
Leaf tructural characteristics are less important than leaf chemical properties in determining the response of leaf mass per area and photosynthesis of Eucalyptus saligna to industrial-age changes in [ CO 2 ] and temperature
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发表时间：
2012
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通讯作者：
M. Greco;A. Chiappetta;L. Bruno;M. B. Bitonti
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作者：
M. Greco;A. Chiappetta;L. Bruno;M. B. Bitonti
在哺乳动物中，镉被广泛认为是一种非遗传毒性致癌物质，通过甲基化依赖的表观遗传机制发挥作用。在这里，镉处理的DNA甲基化模式的影响，检查连同其对染色质重构Posidonia oceanica。DNA甲基化水平和模式进行了分析，在积极生长的器官，短期（6小时）和长期（2天或4天）的长期和低（10 mM）和高（50 mM）剂量的镉，通过甲基化敏感性扩增多态性技术和免疫细胞学方法，分别。还通过qRT-PCR评估了染色甲基化酶（CMT）家族的一个成员（一种DNA甲基转移酶）的表达。透射电镜观察细胞核染色质超微结构。镉处理诱导的DNA甲基化，以及CMT的上调，表明从头甲基化确实发生。高剂量镉可导致间期细胞核进行性异染色质化，长期染毒后可观察到细胞凋亡。这些数据表明，镉干扰的DNA甲基化状态，通过参与一个特定的甲基转移酶。这种变化与核染色质重构有关，可能建立表达/抑制染色质的新平衡。总体而言，这些数据显示了植物Cd毒性机制的表观遗传学基础。
In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short(6 h) and long(2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.