title: Epigenetic Regulation of Dopamine Transporter mRNA Expression in Human Neuroblastoma Cells.
abstract: The dopamine transporter (DAT) is a key regulator of dopaminergic neurotransmission. As such, proper regulation of DAT expression is important to maintain homeostasis, and disruption of DAT expression can lead to neurobehavioral dysfunction. Based on genomic features within the promoter of the DAT gene, there is potential for DAT expression to be regulated through epigenetic mechanisms, including DNA methylation and histone acetylation. However, the relative contribution of these mechanisms to DAT expression has not been empirically determined. Using pharmacologic and genetic approaches, we demonstrate that inhibition of DNA methyltransferase (DNMT) activity increased DAT mRNA approximately 1.5-2 fold. This effect was confirmed by siRNA knockdown of DNMT1. Likewise, the histone deacetylase (HDAC) inhibitors valproate and butyrate also increased DAT mRNA expression, but the response was much more robust with expression increasing over tenfold. Genetic knockdown of HDAC1 by siRNA also increased DAT expression, but not to the extent seen with pharmacological inhibition, suggesting additional isoforms of HDAC or other targets may contribute to the observed effect. Together, these data identify the relative contribution of DNMTs and HDACs in regulating expression. These finding may aid in understanding the mechanistic basis for changes in DAT expression in normal and pathophysiological states.
authors.affiliation: Department of Environmental and Occupational Medicine, Environmental and Occupational Health Sciences Institute, Rutgers Robert Wood Johnson Medical School, 170 Frelinghuysen Rd., Piscataway, NJ, 08854, USA.
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Green
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Hossain
authors.forename: Siew C
authors.initials: SC
authors.lastname: Tee
authors.forename: Helmut
authors.initials: H
authors.lastname: Zarbl
authors.forename: Grace L
authors.initials: GL
authors.lastname: Guo
authors.forename: Jason R
authors.initials: JR
authors.lastname: Richardson
mesh_terms: D045744:Cell Line, Tumor; D015254:DNA Modification Methylases / Q000235:genetics; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D044127:Epigenesis, Genetic; D055785:Gene Knockdown Techniques; D006655:Histone Deacetylases / Q000235:genetics; D006801:Humans; D009447:Neuroblastoma / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D015254:DNA Modification Methylases; D006655:Histone Deacetylases