title: Induction of cell cycle arrest and morphological differentiation by Nurr1 and retinoids in dopamine MN9D cells.
abstract: Dopamine cells are generated in the ventral midbrain during embryonic development. The progressive degeneration of these cells in patients with Parkinson's disease, and the potential therapeutic benefit by transplantation of in vitro generated dopamine cells, has triggered intense interest in understanding the process whereby these cells develop. Nurr1 is an orphan nuclear receptor essential for the development of midbrain dopaminergic neurons. However, the mechanism by which Nurr1 promotes dopamine cell differentiation has remained unknown. In this study we have used a dopamine-synthesizing cell line (MN9D) with immature characteristics to analyze the function of Nurr1 in dopamine cell development. The results demonstrate that Nurr1 can induce cell cycle arrest and a highly differentiated cell morphology in these cells. These two functions were both mediated through a DNA binding-dependent mechanism that did not require Nurr1 interaction with the heterodimerization partner retinoid X receptor. However, retinoids can promote the differentiation of MN9D cells independently of Nurr1. Importantly, the closely related orphan receptors NGFI-B and Nor1 were also able to induce cell cycle arrest and differentiation. Thus, the growth inhibitory activities of the NGFI-B/Nurr1/Nor1 orphan receptors, along with their widespread expression patterns both during development and in the adult, suggest a more general role in control of cell proliferation in the developing embryo and in adult tissues.
authors.affiliation: Ludwig Institute for Cancer Research, Box 240, S-171 77 Stockholm, Sweden.
authors.forename: D S
authors.initials: DS
authors.lastname: Castro
authors.forename: E
authors.initials: E
authors.lastname: Hermanson
authors.forename: B
authors.initials: B
authors.lastname: Joseph
authors.forename: A
authors.initials: A
authors.lastname: Wallén
authors.forename: P
authors.initials: P
authors.lastname: Aarnisalo
authors.forename: A
authors.initials: A
authors.lastname: Heller
authors.forename: T
authors.initials: T
authors.lastname: Perlmann
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology*; D001973:Bromodeoxyuridine / Q000378:metabolism; D002453:Cell Cycle; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D004298:Dopamine / Q000737:chemistry*; D016193:G1 Phase; D017930:Genes, Reporter; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D011987:Receptors, Steroid; D011988:Receptors, Thyroid Hormone; D047488:Retinoid X Receptors; D012176:Retinoids / Q000494:pharmacology*; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; C539882:NR4A2 protein, human; C490412:NR4A3 protein, human; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D018168:Receptors, Retinoic Acid; D011987:Receptors, Steroid; D011988:Receptors, Thyroid Hormone; D047488:Retinoid X Receptors; D012176:Retinoids; D014157:Transcription Factors; D004247:DNA; D001973:Bromodeoxyuridine; D004298:Dopamine