title: DNA methyltransferases1 (DNMT1) and 3a (DNMT3a) colocalize with GAD67-positive neurons in the GAD67-GFP mouse brain.
abstract: DNA methylation is an epigenetic regulatory mechanism commonly associated with transcriptional silencing. DNA methyltransferases (DNMTs) are a family of related proteins that both catalyze the de novo formation of 5-methylcytosine and maintain these methylation marks in cell-specific patterns in virtually all mitotic cells of the body. In the adult brain, methylation occurs in progenitor cells of the neurogenic zones and in postmitotic neurons. Of the DNMTs, DNMT1 and DNMT3a are most highly expressed in postmitotic neurons. While it has been commonly thought all postmitotic neurons and glia express DNMTs at comparable levels, the coexpression of selected DNMTs with markers of distinct neurotransmitter phenotypes has not been previously examined in detail in the mouse. To this end, we analyzed the expression of DNMT1 and DNMT3a along with GAD67 in the brains of the glutamic acid decarboxylase67-enhanced green fluorescent protein (GAD67-GFP) knockin mice. After first confirming that GFP-immunopositive neurons were also GAD67-positive, we showed that in the motor cortex, piriform cortex, striatum, CA1 region of the hippocampus, dentate gyrus, and basolateral amygdala (BLA), GFP immunofluorescence coincided with the signal corresponding to DNMT1 and DNMT3a. A detailed examination of cortical neurons, showed that ≈30% of NeuN-immunopositive neurons were also DNMT1-positive. These data do not exclude the expression of DNMT1 or DNMT3a in glutamatergic neurons and glia. However, they suggest that their expression is low compared with the levels present in GABAergic neurons.
authors.affiliation: Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Bashkim
authors.initials: B
authors.lastname: Kadriu
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guidotti
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Grayson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D000090205:DNA Methyltransferase 3A; D005786:Gene Expression Regulation / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009474:Neurons / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
chemical_list: C000715535:Dnmt3a protein, mouse; D050599:Vesicular Glutamate Transport Protein 2; D049452:Green Fluorescent Proteins; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; C000619381:Dnmt1 protein, mouse; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D010751:Phosphopyruvate Hydratase