Identification of ATF-2 as a transcriptional regulator for the tyrosine hydroxylase gene.
Transcriptional regulation of catecholamine-synthesizing genes is important for the determination of neurotransmitters during brain development. We found that three catecholamine-synthesizing genes were transcriptionally up-regulated in cloned PC12D cells overexpressing V-1, a protein that is highly expressed during postnatal brain development (1). To reveal the molecular mechanism to regulate the expression of tyrosine hydroxylase (TH), which is the rate-limiting enzyme for catecholamine biosynthesis, we analyzed the transcription factors responsible for TH induction in the V-1 clonal cells. First, by using reporter constructs, we found that the transcription mediated by cAMP-responsive element (CRE) was selectively enhanced in the V-1 cells, and TH promoter activity was totally dependent on the CRE in the promoter region of the TH gene. Next, immunoblot analyses and a transactivation assay using a GAL4 reporter system revealed that ATF-2, but not cAMP-responsive element-binding protein (CREB), was highly phosphorylated and activated in the V-1 cells, while both CREB and ATF-2 were bound to the TH-CRE. Finally, the enhanced TH promoter activity was competitively attenuated by expression of a plasmid containing the ATF-2 transactivation domain. These data demonstrated that activation of ATF-2 resulted in the increased transcription of the TH gene and suggest that ATF-2 may be deeply involved in the transcriptional regulation of catecholamine-synthesizing genes during neural development.
Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
Takahiro
T
Suzuki
Tohru
T
Yamakuni
Masatoshi
M
Hagiwara
Hiroshi
H
Ichinose
D051698:Activating Transcription Factor 2; D000818:Animals; D001483:Base Sequence; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology*; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D016716:PC12 Cells; D011401:Promoter Regions, Genetic; D051381:Rats; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics*
D051698:Activating Transcription Factor 2; C497107:Atf2 protein, rat; D017362:Cyclic AMP Response Element-Binding Protein; D017931:DNA Primers; D014157:Transcription Factors; D014446:Tyrosine 3-Monooxygenase