Cross-talk between the HIF-1 and glucocorticoid-signaling pathways is mediated by the glucocorticoid receptor and HREs. (A) The 72-hpf Tg(4xhre-tata:eGFP)ia21 embryos were incubated with different concentrations of DEX. DEX activates the 4xhre-tata transgene. (Magnification: 8×.) (B) Images of 72-hpf Tg(4xhre-tata:eGFP)ia21 larvae injected with a gr-MO and a CTRL-MO alone or combined with DEX (Bottom). DEX activation of 4xhre-tata transgene expression is maintained in CTRL-MO–injected larvae and ablated in GR morphants. (Magnification: 8×.) (C) Histograms showing the average values (±SEM) of the fluorescence-integrated density in 72-hpf Tg(4xhre-tata:eGFP)ia21 embryos injected with gr-MO and CTRL-MO with or without DEX. A.U., Arbitrary units. (D) Fold changes (±SEM) in phd3 gene expression in 72-hpf embryos injected with gr-MO and CTRL-MO with or without DEX (24 h) compared with nontreated/noninjected controls (set at 1). Target gene mRNA levels were normalized to β-actin. *P < 0.05; ***P < 0.001.
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