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Activation of beta-catenin signalling increases StarD7 gene expression in JEG-3 cells.
Rena, V; Angeletti, S; Panzetta-Dutari, G; Genti-Raimondi, S.
Afiliação
  • Rena V; Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Córdoba, Argentina.
Placenta ; 30(10): 876-83, 2009 Oct.
Article em En | MEDLINE | ID: mdl-19679347
StarD7 gene encodes a protein that belongs to the StAR-related lipid transfer proteins involved in intracellular transport and metabolism of lipids. It has been previously documented that StarD7 has a wide-spread mRNA expression in trophoblastic tissues and several tumour cell lines with highest levels in both choriocarcinoma JEG-3 and JAR cells, hepatocellular carcinoma HepG2, and colorectal adenocarcinoma HT-29 cells. To understand the molecular mechanisms that regulate the expression of the human StarD7 gene, we have cloned and characterized the 5'-flanking region of the gene. Transient transfections of several 5'deleted StarD7-promoter-firefly luciferase constructs into JEG-3 cells indicated that the -312/+157 region contains the gene minimal promoter. In addition, sequence analysis of a 1.6kb gene fragment revealed the presence of a TATA-less promoter as well as multiple regulatory motifs, including one regulatory element corresponding to the T-cell factor 4 (TCF4) binding site. Inhibition of glycogen synthase kinase-3beta (GSK3beta), a component of Wnt/beta-catenin signalling, increased both StarD7 mRNA and protein expression as well as its promoter activity. Co-transfection experiments in JEG-3 cell line revealed that the StarD7 promoter is activated by TCF4 transcription factor and by its beta-catenin coactivator. Moreover, site-directed mutagenesis of the TCF4 site located -614/-608bp relative to the transcription start site markedly diminished StarD7 promoter activity. Chromatin immunoprecipitation analysis demonstrated that beta-catenin and TCF4 are bound in vivo to the StarD7 gene promoter in JEG-3 cells treated with lithium chloride. Collectively, these studies show that beta-catenin and TCF4 activate the human StarD7 gene interacting with its promoter region through Wnt/beta-catenin signalling.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transdução de Sinais / Proteínas de Transporte / Regulação Neoplásica da Expressão Gênica / Beta Catenina Limite: Humans Idioma: En Revista: Placenta Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Argentina País de publicação: Holanda

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transdução de Sinais / Proteínas de Transporte / Regulação Neoplásica da Expressão Gênica / Beta Catenina Limite: Humans Idioma: En Revista: Placenta Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Argentina País de publicação: Holanda