Figure 4

CG6672 (dZnT7) , the Drosophila ortholog of hZnT7 , is not directly involved in dietary zinc absorption. (A) hZnT7, but not dZnT1, partially rescues dZnT7 after RNA interference (RNAi). Ubiquitous knockdown of dZnT7 caused lethality to the wandering larvae, but with hZnT7 these flies reached the late pupal or even adult stage. (B) RT-PCR analysis of the knockdown effect of dZnT7-RNAi lines at third-instar larval stage. rp49 was used as the loading control. (C) Golgi localization of dZnT7 in Caco-2 cells. Fluorescence markers; enhanced green fluorescent protein (eGFP)-tagged dZnT7 (green); red fluorescent protein (RFP)-tagged Golgi-targeted peptide (red); merged image (yellow) of dZnT7 and Golgi markers. Scale bars = 10 μm. (D) The activity of alkaline phosphatase (ALP), but not aconitase, was significantly reduced in larvae with dZnT7-RNAi driven by da-GAL4. (E) Gut-specific knockdown of dZnT7 could not reduce the ALP activity of the whole body, although the ubiquitous silencing causes significant reduction. (F) ALP activity of whole body minus gut in gut-specific RNAi of intracellular ZnTs on zinc-limited (0.3 mmol/l EDTA) food. Neither dZnT7, nor any other intracellular ZnT transporters, had any discernible effect on zinc availability for the rest of the body. NP3084 was crossed with individual RNAi lines. Values are presented as means ± SEM; n ≥ 3. *P < 0.05, **P < 0.01, ***P < 0.001; one-way ANOVA.