Fig. 4. Erythropoietin stimulation of neuronal cells. (A) Erythropoietin (5 U ml–1) stimulated NT2 cell proliferation when cultured under 2% oxygen tension for 3 days. (B) Epor expression was induced in NT2 cells cultured with 5% CO2 and 2% O2 compared with 20% O2, determined by quantitative RT-PCR using Taqman probes. (C) GATA3 production was induced by erythropoietin stimulation. (D) Epor expression was induced in NT2 cells overexpressing GATA3. (E) In transfection assays, the human Epor promoter was linked to a luciferase reporter gene to assess Epor promoter activity in NT2 cells. GATA3 production induced Epor promoter activity (EpoR). Mutation of the GATA motif (
EpoR) markedly decreases promoter activity. (F) GATA3 expression was downregulated in E10.5 Epor–/– cortex (solid bar) compared with expression in the Epor+/+ cortex (open bar).
