title: No evidence for AID/MBD4-coupled DNA demethylation in zebrafish embryos.
abstract: The mechanisms responsible for active DNA demethylation remain elusive in Metazoa. A previous study that utilized zebrafish embryos provided a potent mechanism for active demethylation in which three proteins, AID, MBD4, and GADD45 are involved. We recently found age-dependent DNA hypomethylation in zebrafish, and it prompted us to examine if AID and MBD4 could be involved in the phenomenon. Unexpectedly, however, we found that most of the findings in the previous study were not reproducible. First, the injection of a methylated DNA fragment into zebrafish eggs did not affect either the methylation of genomic DNA, injected methylated DNA itself, or several loci tested or the expression level of aid, which has been shown to play a role in demethylation. Second, aberrant methylation was not observed at certain CpG islands following the injection of antisense morpholino oligonucleotides against aid and mbd4. Furthermore, we demonstrated that zebrafish MBD4 cDNA lacked a coding region for the methyl-CpG binding domain, which was assumed to be necessary for guidance to target regions. Taken together, we concluded that there is currently no evidence to support the proposed roles of AID and MBD4 in active demethylation in zebrafish embryos.
authors.affiliation: Department of Regenerative Medicine, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Obu, Aichi 474-8522, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Shimoda
authors.affiliation: Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hirose
authors.affiliation: Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Reiya
authors.initials: R
authors.lastname: Kaneto
authors.affiliation: Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Izawa
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumi-Dori Amamiya-Machi, Aoba-Ku, Sendai 981-8555, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Yokoi
authors.affiliation: Department of Regenerative Medicine, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Obu, Aichi 474-8522, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Hashimoto
authors.affiliation: Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kikuchi
mesh_terms: D017398:Alternative Splicing / Q000187:drug effects / Q000235:genetics; D000818:Animals; D018899:CpG Islands / Q000235:genetics; D003564:Cytidine Deaminase / Q000235:genetics / Q000378:metabolism*; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000378:metabolism*; D005306:Fertilization / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D016678:Genome; D007267:Injections; D060172:Morpholinos / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010063:Ovum / Q000187:drug effects / Q000378:metabolism; D017434:Protein Structure, Tertiary; D014158:Transcription, Genetic / Q000187:drug effects; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D060172:Morpholinos; D029961:Zebrafish Proteins; D045647:DNA Glycosylases; C000600492:MBD4 protein, zebrafish; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase