gr loss of function effect is stronger when HIF-signalling is moderately upregulated. A-E. Representative picture of the main differences between vhl-/-, arnt1-/-;vhl-/-, gr-/-;vhl-/- and triple gr-/-;arnt1-/-;vhl-/- larvae at 5 dpf. Among the 488 phd3:eGFP expressing larvae analysed, 7 larvae were characterized by the absence of pericardial oedema (black arrowheads, left), no ectopic extra vasculature at the level of the tail (black arrowheads, right), no visible phd3:eGFP HIF reporter in the liver (white arrowheads, left) and even more reduced levels of this marker in the head and in the rest of the body (white arrowheads, right). Genotypic analysis allowed to confirm the presence of a genotype-phenotype correlation in 5 out 7 samples and to prove that they were triple mutants. Fluorescence, exposure = 2 seconds. Scale bar 200 μm. F-I. Representative pictures of WISH performed on gr+/-; vhl+/- incross derived larvae, at 5 dpf, using pomca as probe. Of note, gr-/-;vhl-/- showed upregulated pomca expression (20/20 larvae), as observed in gr-/- (20/20 larvae); vhl mutants showed downregulated pomca expression (20/20 larvae), whereas wildtypes showed normal pomca expression (19/20). Chi-square test (****P < 0.0001). Scale bar 50 μm.
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