Nurr1 enhances transcription of the human dopamine transporter gene through a novel mechanism.
The importance of the nuclear receptor nurr1 for the appropriate development of mesencephalic dopamine-synthesizing neurons has been clearly demonstrated through the targeted disruption of the nurr1 gene. The persistence of nurr1 expression in adult tissue suggests a possible role for this transcription factor in the maintenance, as well as development, of the dopaminergic phenotype. To address this issue, we analyzed the effects of nurr1 on the transcriptional expression of the human dopamine transporter gene (hDAT), one of the most specific phenotypic markers for dopaminergic neurons. Nurr1 enhanced the transcriptional activity of hDAT gene constructs transiently transfected into a newly described cell line (SN4741) that expresses a dopaminergic phenotype, whereas other members of the NGFI-B subfamily of nuclear receptors had lesser or no effects. Nurr1 activation of hDAT was not dependent upon heterodimerization with the retinoid X receptor. Unexpectedly, functional analysis of a series of gene constructs revealed that a region of the hDAT 5'-flanking sequence devoid of NGFI-B response element (NBRE)-like sites mediated nurr1 activation. Additional experiments using a nurr1 mutant construct suggest that nurr1 activates hDAT transcription via a novel NBRE-independent mechanism.
Sacchetti
P
P
Department of Psychiatry, Wayne State University School of Medicine, Detroit, USA.
Mitchell
T R
TR
Granneman
J G
JG
Bannon
M J
MJ
D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D004268:DNA-Binding Proteins; D019281:Dimerization; D050483:Dopamine Plasma Membrane Transport Proteins; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006657:Histones / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008636:Mesencephalon / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013378:Substantia Nigra / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D006657:Histones; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; C539882:NR4A2 protein, human; D009419:Nerve Tissue Proteins; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D014157:Transcription Factors; D008156:Luciferases