title: Egr-1 induces DARPP-32 expression in striatal medium spiny neurons via a conserved intragenic element.
abstract: DARPP-32 (dopamine and adenosine 3', 5'-cyclic monophosphate cAMP-regulated phosphoprotein, 32 kDa) is a striatal-enriched protein that mediates signaling by dopamine and other first messengers in the medium spiny neurons. The transcriptional mechanisms that regulate striatal DARPP-32 expression remain enigmatic and are a subject of much interest in the efforts to induce a striatal phenotype in stem cells. We report the identification and characterization of a conserved region, also known as H10, in intron IV of the gene that codes for DARPP-32 (Ppp1r1b). This DNA sequence forms multiunit complexes with nuclear proteins from adult and embryonic striata of mice and rats. Purification of proteins from these complexes identified early growth response-1 (Egr-1). The interaction between Egr-1 and H10 was confirmed in vitro and in vivo by super-shift and chromatin immunoprecipitation assays, respectively. Importantly, brain-derived neurotrophic factor (BDNF), a known inducer of DARPP-32 and Egr-1 expression, enhanced Egr-1 binding to H10 in vitro. Moreover, overexpression of Egr-1 in primary striatal neurons induced the expression of DARPP-32, whereas a dominant-negative Egr-1 blocked DARPP-32 induction by BDNF. Together, this study identifies Egr-1 as a transcriptional activator of the Ppp1r1b gene and provides insight into the molecular mechanisms that regulate medium spiny neuron maturation.
authors.affiliation: Department of Neurology and Pediatrics, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: Serene
authors.initials: S
authors.lastname: Keilani
authors.forename: Samira
authors.initials: S
authors.lastname: Chandwani
authors.forename: Georgia
authors.initials: G
authors.lastname: Dolios
authors.forename: Alexey
authors.initials: A
authors.lastname: Bogush
authors.forename: Heike
authors.initials: H
authors.lastname: Beck
authors.forename: Antonis K
authors.initials: AK
authors.lastname: Hatzopoulos
authors.forename: Gadiparthi N
authors.initials: GN
authors.lastname: Rao
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Thomas
authors.forename: Rong
authors.initials: R
authors.lastname: Wang
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Ehrlich
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000096:biosynthesis* / Q000235:genetics*; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D007438:Introns / Q000235:genetics*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D061251:Primary Cell Culture; D011485:Protein Binding / Q000235:genetics; D051381:Rats; D016415:Sequence Alignment / Q000379:methods; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D051766:Early Growth Response Protein 1; D009419:Nerve Tissue Proteins; D014157:Transcription Factors