The Cation Diffusion Facilitator Gene cdf-2 Mediates Zinc Metabolism in Caenorhabditis elegans

Abstract

Zinc is essential for many cellular processes. To use Caenorhabditis elegans to study zinc metabolism, we developed culture conditions allowing full control of dietary zinc and methods to measure zinc content of animals. Dietary zinc dramatically affected growth and zinc content; wild-type worms survived from 7 mm to 1.3 mm dietary zinc, and zinc content varied 27-fold. We investigated cdf-2, which encodes a predicted zinc transporter in the cation diffusion facilitator family. cdf-2 mRNA levels were increased by high dietary zinc, suggesting cdf-2 promotes zinc homeostasis. CDF-2 protein was expressed in intestinal cells and localized to cytosolic vesicles. A cdf-2 loss-of-function mutant displayed impaired growth and reduced zinc content, indicating that CDF-2 stores zinc by transport into the lumen of vesicles. The relationships between three cdf genes, cdf-1, cdf-2, and sur-7, were analyzed in double and triple mutant animals. A cdf-1 mutant displayed increased zinc content, whereas a cdf-1 cdf-2 double mutant had intermediate zinc content, suggesting cdf-1 and cdf-2 have antagonistic functions. These studies advance C. elegans as a model of zinc metabolism and identify cdf-2 as a new gene that has a critical role in zinc storage.

Lysosome-Related Organelles in Intestinal Cells Are a Zinc Storage Site in C. elegans

“…By using inductively coupled plasma-mass spectrometry (ICP-MS) to measure total zinc content in worm extracts, we demonstrated that C. elegans cultured with high dietary zinc display elevated levels of total zinc, suggesting excess zinc is stored (Davis et al, 2009). To identify the site of zinc storage, we used zinc-specific fluorescent dyes to visualize zinc.…”

“…To study zinc metabolism, we developed methods to manipulate dietary zinc and used forward and reverse genetic approaches to identify genes important for zinc metabolism (Bruinsma et al, 2008; Davis et al, 2009; Murphy et al, 2011). C. elegans contains highly conserved families of CDF, ZIP and metallothionein genes, suggesting that fundamental mechanisms of zinc metabolism may be similar to other animals.…”

“…C. elegans contains highly conserved families of CDF, ZIP and metallothionein genes, suggesting that fundamental mechanisms of zinc metabolism may be similar to other animals. In response to a high zinc diet, C. elegans accumulates zinc (Davis et al, 2009). To characterize zinc storage and mobilization, we developed methods to visualize zinc in C. elegans using a zinc-specific fluorescent dye.…”

The Intestinal Copper Exporter CUA-1 Is Required for Systemic Copper Homeostasis in Caenorhabditis elegans

“…For these reasons, we utilized C. elegans, which has been widely used in the study of the metabolism of other metals, including iron, heme, and zinc (8,(13)(14)(15)(16)(17). Although mammals have two copper exporters, serving complementary functions in different tissues such as the gut and liver, lower metazoans (including nematodes (C. elegans) and insects (Drosophila melanogaster)) have only a single homolog of ATP7A/B (2,18,19).…”

New links between protein N-terminal acetylation, dauer diapause, and the insulin/IGF-1 signaling pathway inCaenorhabditis elegans

“…8 To identify genes involved in this type of stress resistance, Bruinsma et al (2008) performed a forward genetic screen for worms that are resistant to the toxicity caused by high levels of dietary zinc and isolated 2 mutations in natc-1. 9 Warnhoff et al (2014) identified the affected gene by positional cloning and demonstrated that the natc-1(am138) and natc-1 (am134) mutations cause a strong loss-offunction.…”