title: Methyl-CpG binding proteins are involved in restricting differentiation plasticity in neurons.
abstract: Neurons and astrocytes are generated from common neural precursors, yet neurogenesis precedes astrocytogenesis, which normally commences at later stages of development. We have previously reported that a particular cytosine residue within a STAT3-binding site in the astrocyte-specific marker glial fibrillary acidic protein (GFAP) gene promoter becomes demethylated in neuroepithelial cells as gestation proceeds. This demethylation correlates tightly with the onset of astrocyte differentiation, suggesting that a change in DNA methylation at cell-type-specific gene promoters controls the switch from neurogenesis to astrocytogenesis in the developing brain. Here, we show that late-gestation neuroepithelial cells, which have already lost the methylation in the STAT3-binding site within the GFAP promoter, can still give rise to neurons and that these neurons do not respond to a STAT3-activating cytokine to express GFAP. Members of a transcriptional repressor family, the methylated-CpG binding proteins (MBDs), including MeCP2, are predominantly expressed in neurons, and ectopic MeCP2 expression inhibited astrocyte differentiation of neuroepithelial cells. Moreover, we found that exon 1 of the GFAP gene remains hypermethylated even in neuroepithelial cells at a late developmental stage and in neurons differentiated from such neuroepithelial cells. We further demonstrate that MeCP2 actually binds to the highly methylated exon 1 of the GFAP gene in neurons. These results suggest that region-specific DNA methylation and MBDs play an important role in the regulation of differentiation plasticity in neurons.
authors.affiliation: Laboratory of Molecular Neuroscience, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan. kin@bs.naist.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Setoguchi
authors.forename: Masakazu
authors.initials: M
authors.lastname: Namihira
authors.forename: Jun
authors.initials: J
authors.lastname: Kohyama
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Asano
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sanosaka
authors.forename: Kinichi
authors.initials: K
authors.lastname: Nakashima
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000737:chemistry; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation / Q000379:methods; D016207:Cytokines / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000502:physiology; D004622:Embryo, Mammalian; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D051783:Methyl-CpG-Binding Protein 2 / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D009419:Nerve Tissue Proteins / Q000378:metabolism; D046569:Neuroepithelial Cells / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011247:Pregnancy; D051381:Rats; D014162:Transfection / Q000379:methods; D014404:Tubulin / Q000378:metabolism
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; C489324:Mbd1 protein, rat; C497393:Mecp2 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; D009419:Nerve Tissue Proteins; D014404:Tubulin; C462941:beta3 tubulin, mouse