Regulation of GTP cyclohydrolase I expression by orphan receptor Nurr1 in cell culture and in vivo.
Nurr1 is an orphan nuclear transcription factor essential for the terminal differentiation of dopamine (DA) neurons in the ventral midbrain (VM). To identify the Nurr1-target genes, we carried out microarray and quantitative real-time PCR analyses of Nurr1 null and wild-type mice in VM at embryonic day (E) 12.5 and shortly after birth (P0). In addition to the absence of mRNAs of DA synthesizing enzymes, the guanosine 5'-triphosphate (GTP) cyclohydrolase I (GTPCH) was also substantially reduced in the VM of Nurr1-null mice. GTPCH is the first enzyme in the synthesis pathway of tetrahydrobiopterin (BH4), an essential cofactor for tyrosine hydroxylase in DA synthesis. In the mouse, Nurr1 and GTPCH mRNA were first detected at E10.5, and GTPCH transcription paralleled that of Nurr1. Small interfering RNA targeted against Nurr1 decreases GTPCH expression in MC3T3-E1 osteoblasts in cell culture. Cotransfection of Nurr1 and the GTPCH-luciferase (luc) reporter increased the luc activity by about threefold in N2A cells. Additional analysis using 5'-deletions and mutants revealed that Nurr1 activates GTPCH transcription indirectly through the proximal promoter region, in the absence of the nerve growth factor-induced clone B (NGFI-B) responsive element-like sites, similarly, as recently reported for DA transporter regulation by Nurr1.
Gil
Minchan
M
Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
McKinney
Cushla
C
Lee
Mi Kyeong
MK
Eells
Jeffrey B
JB
Phyillaier
Marcia A
MA
Nikodem
Vera M
VM
D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives / Q000096:biosynthesis; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004298:Dopamine / Q000096:biosynthesis; D015536:Down-Regulation / Q000235:genetics; D004789:Enzyme Activation / Q000235:genetics; D005260:Female; D006136:GTP Cyclohydrolase / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D017930:Genes, Reporter / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D034741:RNA, Small Interfering; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D011987:Receptors, Steroid / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C539818:Nr4a1 protein, mouse; C539883:Nr4a2 protein, mouse; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D001708:Biopterins; D006136:GTP Cyclohydrolase; C003402:sapropterin; D004298:Dopamine