title: OTX2 regulates expression of DOPAchrome tautomerase in human retinal pigment epithelium.
abstract: Otx2 is a member of homeodomain-containing transcription factors and is essential for eye morphogenesis in mice. Here we show the expression of OTX2, the human counterpart of Otx2, in cell lines of retinal pigment epithelium (RPE) and in Y79 retinoblastoma cells that exhibit the property of presumptive RPE. These RPE cells express DOPAchrome tautomerase (DCT) that is an enzyme involved in melanin biosynthesis. DCT may contribute to the homeostasis of RPE by detoxifying DOPA-derived metabolites. OTX2 binds to the DCT gene promoter in vivo, as judged by chromatin immunoprecipitation assays. Furthermore, repression of endogenous OTX2 expression in Y79 cells by an anti-sense OTX2 oligonucleotide resulted in the decrease of DCT protein contents. Transient expression assays revealed that OTX2 activated the DCT gene promoter through the OTX-2-binding site in an RPE-specific manner. Therefore, OTX2 may regulate RPE-specific target genes, such as DCT, thereby maintaining the homeostasis of RPE.
authors.affiliation: Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takeda
authors.forename: Satoru
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Ken ichi
authors.initials: Ki
authors.lastname: Yasumoto
authors.forename: Hideo
authors.initials: H
authors.lastname: Saito
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Udono
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Shibahara
mesh_terms: D000293:Adolescent; D000818:Animals; D002460:Cell Line; D002648:Child; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D051857:Otx Transcription Factors; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; C497659:OTX2 protein, human; D016376:Oligonucleotides, Antisense; D051857:Otx Transcription Factors; C497660:Otx2 protein, mouse; D015534:Trans-Activators; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase