Identification of the copper chaperone, CUC‐1, in Caenorhabditis elegans: tissue specific co‐expression with the copper transporting ATPase, CUA‐1

Abstract
A cDNA encoding a putative copper chaperone protein, CUC‐1, was cloned from Caenorhabditis elegans. CUC‐1 had the characteristic motifs of MTCXXC and KKTGK, and showed 49.3 and 39.1% sequence identity with yeast Atx1p and human HAH1, respectively. Expression of CUC‐1 cDNA complemented a null atx1 mutant, the yeast copper chaperone gene, thus demonstrating that CUC‐1 is a functional copper chaperone. Studies with transgenic worms indicated that cuc‐1 and cua‐1, which encodes the copper transporting ATPase, are expressed together in intestinal cells of adult and hypodermal cells in the larvae. cua‐1 was also expressed in pharyngeal muscle but cuc‐1 was not. These results suggest that CUC‐1 and CUA‐1 constitute a copper trafficking pathway similar to the yeast counterparts in intestinal and hypodermal cells, and CUA‐1 may have a different function in pharyngeal muscle.