title: Verification of the in vivo activity of three distinct cis-acting elements within the Gata1 gene promoter-proximal enhancer in mice.
abstract: The transcription factor GATA1 is essential for erythroid and megakaryocytic cell differentiation. Gata1 hematopoietic regulatory domain (G1HRD) has been shown to recapitulate endogenous Gata1 gene expression in transgenic mouse assays in vivo. G1HRD contains a promoter-proximal enhancer composed of a GATA-palindrome motif, four CP2-binding sites and two CACCC boxes. We prepared transgenic reporter mouse lines in which green fluorescent protein and β-galactosidase expression are driven by wild-type G1HRD (as a positive control) and the G1HRD harboring mutations within these cis-acting elements (as the experimental conditions), respectively. Exploiting this transgenic dual reporter (TDR) assay, we show here that in definitive erythropoiesis, G1HRD activity was markedly affected by individual mutations in the GATA-palindrome motif and the CACCC boxes. Mutation of CP2-binding sites also moderately decreased G1HRD activity. The combined mutation of the CP2-binding sites and the GATA-palindrome motif resulted in complete loss of G1HRD activity. In contrast, in primitive erythroid cells, individual mutations of each element did not affect G1HRD activity; G1HRD activity was abolished only when these three mutations were combined. These results thus show that all three elements independently and cooperatively contribute to G1HRD activity in vivo in definitive erythropoiesis, although these are contributing redundantly to primitive erythropoiesis.
authors.affiliation: Department of Molecular Hematology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Shimizu
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Sergio
authors.initials: S
authors.lastname: Ottolenghi
authors.forename: Antonella
authors.initials: A
authors.lastname: Ronchi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D004742:Enhancer Elements, Genetic; D004920:Erythropoiesis; D050982:GATA1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D017930:Genes, Reporter; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: D050982:GATA1 Transcription Factor