title: Daily variation in global and local DNA methylation in mouse livers.
abstract: DNA methylation is one of the best-characterized epigenetic modifications and has an important biological relevance. Here we showed that global DNA methylation level in mouse livers displayed a daily variation where the peak phases occurred during the end of the day and the lowest level at the beginning of the day in the light-dark or dark-dark cycles. Typical repeat sequence long interspersed nucleotide element-1 (LINE-1) had a similar methylation rhythm to global DNA. DNA methyltransferase 3A (DNMT3A) and ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) brought a relative forward daily variation to global DNA methylation, and the temporary change in ratio of SAM to SAH had no influence on the DNA methylation level. The rhythm of global DNA methylation was lost and DNA methylation level was increased in Per1-/-Per2-/- double knockout mice, which were in accordance with changes of Dnmt3a mRNA levels and its rhythm. Our results suggest that the daily variation in global DNA methylation was associated with the change of Dnmt3a expression rather than ratio of SAM to SAH.
authors.affiliation: Center for Molecular Metabolism, Nanjing University of Science & Technology, Nanjing, 210094, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xia
authors.affiliation: Nanjing Institute for the Comprehensive Utilization of Wild Plant, Nanjing, 210042, China.
authors.forename: Shihong
authors.initials: S
authors.lastname: Ma
authors.affiliation: Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, 212013, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Center for Molecular Metabolism, Nanjing University of Science & Technology, Nanjing, 210094, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Center for Molecular Metabolism, Nanjing University of Science & Technology, Nanjing, 210094, China.
authors.forename: Mengyi
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Department of Radiology, Nanjing University of Chinese Medicine, Nanjing, 210000, China.
authors.forename: Zhongqiu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Center for Molecular Metabolism, Nanjing University of Science & Technology, Nanjing, 210094, China.
authors.forename: Jianfa
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics; D019175:DNA Methylation / Q000502:physiology*; D000090205:DNA Methyltransferase 3A; D004268:DNA-Binding Proteins / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D055786:Gene Knockout Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D056950:Period Circadian Proteins / Q000172:deficiency / Q000235:genetics; D012435:S-Adenosylhomocysteine / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C000715535:Dnmt3a protein, mouse; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D012436:S-Adenosylmethionine; D012435:S-Adenosylhomocysteine; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A