(A, left) Lateral views of WT embryos (a1–b3) and ndrg1a-/- mutants (c1–c3) exposed to anoxia for 0 hr (a1–c1), 6 hr (a2–c2), 12 hr (a3–c3) and immunolabeled with anti-ATP1A1A (green) and anti-Ndrg1a (red); (a1–a3) show merged channels, while (b1–c3) show the green (ATP1A1A) channel only. Annotations: yellow and green boxes identify ionocytes that are positive for Ndrg1a and ATP1A1A (yellow) or ATP1A1A-only (green). Scale bar: a1: 100 μm; a1’: 2 μm. (A, right) Higher magnification images of yellow boxed in areas in (a1-b3), showing merged channels (a1’-a3’) and green channel only (b1’-b3’). (B) Normalized fluorescence intensity of ATP1A1A in ionocytes of WT embryos and ndrg1a-/- mutants exposed to anoxia for 0, 6, 12, 18, and 24 hr. (n=3 experiments with an average of 37 ionocytes processed per experimental group; Figure 4—source data 1).