title: In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning.
abstract: 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 μM) and high (50 μM) 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.
authors: Department of Ecology, University of Calabria, Laboratory of Plant Cyto-physiology, Ponte Pietro Bucci, I-87036 Arcavacata di Rende, Cosenza, Italy.
authors: Maria
authors: M
authors: Greco
authors: Adriana
authors: A
authors: Chiappetta
authors: Leonardo
authors: L
authors: Bruno
authors: Maria Beatrice
authors: MB
authors: Bitonti
mesh_terms: D035961:Alismatales / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics* / Q000648:ultrastructure; D001483:Base Sequence; D002104:Cadmium / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002734:Chlorophyll / Q000378:metabolism; D002843:Chromatin / Q000187:drug effects* / Q000648:ultrastructure; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics*; D019175:DNA Methylation / Q000187:drug effects*; D044127:Epigenesis, Genetic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018745:Genome, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves; D010940:Plant Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D002273:Carcinogens; D002843:Chromatin; D010940:Plant Proteins; D002104:Cadmium; D002734:Chlorophyll; D004248:DNA (Cytosine-5-)-Methyltransferases; C112810:chromomethylase