Gene expression profile in human cells exposed to zinc

Although Zn is an essential trace metal for humans, a comprehensive view of its effects on cellular functions has not been obtained. We used a DNA microarray to assess transcriptional alterations in human HeLa cells after exposure to a moderate concentration of Zn (100 muM ZnSO(4)). Out of 9,182 human genes, expression was increased in 7 genes and decreased in 4 genes twofold or greater. Four of the 7 upregulated genes were those coding for metallothionein isoforms or related proteins. An unexpectedly small extent of changes in gene expression might reflect rapid sequestration of Zn ions by metallothioneins, and the absence of most of the other protective responses indicated the non-toxic nature of Zn at this concentration. Comparison with our previous DNA microarray results for 5 muM CdSO(4)-exposed HeLa cells revealed several genes that are regulated by both metals in parallel, and a gene reciprocally regulated by them.