Parrilla-Doblas, Jara TeresaRoldan-Arjona, TeresaAriza, Rafael RCordoba-Cañero, Dolores2023-01-252023-01-252019-09-19Parrilla-Doblas JT, Roldán-Arjona T, Ariza RR, Córdoba-Cañero D. Active DNA Demethylation in Plants. Int J Mol Sci. 2019 Sep 21;20(19):4683http://hdl.handle.net/10668/14533Methylation of cytosine (5-meC) is a critical epigenetic modification in many eukaryotes, and genomic DNA methylation landscapes are dynamically regulated by opposed methylation and demethylation processes. Plants are unique in possessing a mechanism for active DNA demethylation involving DNA glycosylases that excise 5-meC and initiate its replacement with unmodified C through a base excision repair (BER) pathway. Plant BER-mediated DNA demethylation is a complex process involving numerous proteins, as well as additional regulatory factors that avoid accumulation of potentially harmful intermediates and coordinate demethylation and methylation to maintain balanced yet flexible DNA methylation patterns. Active DNA demethylation counteracts excessive methylation at transposable elements (TEs), mainly in euchromatic regions, and one of its major functions is to avoid methylation spreading to nearby genes. It is also involved in transcriptional activation of TEs and TE-derived sequences in companion cells of male and female gametophytes, which reinforces transposon silencing in gametes and also contributes to gene imprinting in the endosperm. Plant 5-meC DNA glycosylases are additionally involved in many other physiological processes, including seed development and germination, fruit ripening, and plant responses to a variety of biotic and abiotic environmental stimuli.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/5-methylcytosineDNA glycosylasesDNA methylationDNA repairAbiotic stressBase excisionBiotic stressEpigeneticsGene imprintingTransposonsDNA, plantEndospermGene expression regulation, plantGenomic instabilityOvulePlantsPollenStress, physiologicalresearch article31546611open accessADN de plantasEndospermoEstrés fisiológicoInestabilidad genómicaPlantasPolenRegulación de la expresión génica de las plantasÓvulo10.3390/ijms201946831422-0067PMC6801703https://www.mdpi.com/1422-0067/20/19/4683/pdf?version=1569051289https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6801703/pdf