title: Excision of 5-hydroxymethylcytosine by DEMETER family DNA glycosylases.
abstract: In plants and animals, 5-methylcytosine (5mC) serves as an epigenetic mark to repress gene expression, playing critical roles for cellular differentiation and transposon silencing. Mammals also have 5-hydroxymethylcytosine (5hmC), resulting from hydroxylation of 5mC by TET family-enzymes. 5hmC is abundant in mouse Purkinje neurons and embryonic stem cells, and regarded as an important intermediate for active DNA demethylation in mammals. However, the presence of 5hmC in plants has not been clearly demonstrated. In Arabidopsis, the DEMETER (DME) family DNA glycosylases efficiently remove 5mC, which results in DNA demethylation and transcriptional activation of target genes. Here we show that DME and ROS1 have a significant 5hmC excision activity in vitro, although we detected no 5hmC in Arabidopsis, suggesting that it is very unlikely for plants to utilize 5hmC as a DNA demethylation intermediate. Our results indicate that both plants and animals have 5mC in common but DNA demethylation systems have independently evolved with distinct mechanisms.
authors.affiliation: Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Hosung
authors.initials: H
authors.lastname: Jang
authors.affiliation: Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Hosub
authors.initials: H
authors.lastname: Shin
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Brandt F
authors.initials: BF
authors.lastname: Eichman
authors.affiliation: Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea. Electronic address: huhjh@snu.ac.kr.
authors.forename: Jin Hoe
authors.initials: JH
authors.lastname: Huh
mesh_terms: D044503:5-Methylcytosine / Q000378:metabolism / Q000031:analogs & derivatives; D000818:Animals; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003596:Cytosine / Q000031:analogs & derivatives* / Q000378:metabolism; D045647:DNA Glycosylases / Q000378:metabolism*; D019175:DNA Methylation; D051379:Mice; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D009687:Nuclear Proteins; C471271:ROS1 protein, Arabidopsis; D015534:Trans-Activators; C011865:5-hydroxymethylcytosine; D044503:5-Methylcytosine; D003596:Cytosine; C463261:DEMETER protein, Arabidopsis; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases
keywords: 5-Hydroxymethylcytosine; 5-Methylcytosine; DEMETER; DNA demethylation; DNA glycosylase