MTN-EYFP expression in <i>Drosophila</i>.

<p><i>Drosophila</i> expressing a copper-inducible MTN-EYFP construct (green) were reared until third instar on basal media (A, B) and media supplemented with 0.5 mM copper (C, D). Gut tissue incorporating the gastric caecum and anterior midgut (left) to the posterior midgut (right) was dissected from control (A, C) and midgut <i>PSN</i> knockdown (B, D) larvae. MTN-EYFP expression was greater in the gut of control larvae reared on copper-supplemented media(C) than those on basal media (A), indicative of increased copper levels. Under basal condition, MTN-EYFP expression in the gut of PSN knockdown (B) and control (A) larvae was comparable. When reared on copper-supplemented media MTN-EYFP levels were lower in the gut of <i>PSN</i> knockdown larvae (D) than control (C), consistent with reduced copper levels. Western immunoblotting with a GFP antibody was used to confirm MTN-EYFP levels in pooled samples of five larvae reared on basal media and media supplemented with 0.5 mM copper (E). α-Tubulin was used as a loading control. When reared on copper-supplemented media MTN-EYFP levels were lower in the gut of <i>PSN</i> knockdown larvae than control.