A direct role of the homeodomain proteins Phox2a/2b in noradrenaline neurotransmitter identity determination.
Development of noraderenergic (NA) neurons in the vertebrate brain is dependent on the homeodomain proteins Phox2a and 2b. Here, we show that Phox2a directly controls the NA identity by activating NA-synthesizing dopamine beta-hydroxylase (DBH ) gene. Single point mutations in the homeodomain of Phox2a resulted in a failure to transactivate the DBH promoter in vitro and resulted in the loss of NA neurons in vivo. In addition, injection of Phox2a-specific antisense oligonucleotide induced the loss of NA neurons in developing zebrafish. Phox2a and 2b activate the DBH promoter and bind to three domains (PBD1-3). PBD1 is composed of two overlapping sites with which monomers of Phox2a can interact. In contrast, PBD2 and 3 interact with the dimeric form of Phox2a. Mutations in three or four, but not one or two, of the binding sites completely abolished activation of the DBH promoter by Phox2a or 2b, while the conversion of PBD3 to a consensus motif (ATTA) improved the DBH promoter activity by > 10-fold. Taken together, these findings establish that Phox2a and 2b control the development of NA neurons in part by directly transactivating DBH transcription through interactions with four binding sites clustered in the proximal promoter.
Seo
Hyemyung
H
Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts 02478, USA.
Hong
Seok Jong
SJ
Guo
Su
S
Kim
Hee-Sun
HS
Kim
Chun-Hyung
CH
Hwang
Dong-Youn
DY
Isacson
Ole
O
Rosenthal
Arnon
A
Kim
Kwang-Soo
KS
D020121:5' Untranslated Regions / Q000502:physiology; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D002454:Cell Differentiation; D019281:Dimerization; D004299:Dopamine beta-Hydroxylase / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D015027:Zebrafish
D020121:5' Untranslated Regions; D018398:Homeodomain Proteins; C109220:NBPhox protein; D009419:Nerve Tissue Proteins; D016376:Oligonucleotides, Antisense; C491061:PHOX2A protein, human; C100935:Phox2a protein, rat; D014157:Transcription Factors; D004299:Dopamine beta-Hydroxylase; D009638:Norepinephrine