The p53-induced wig-1 gene encodes an unusual nuclear zinc finger protein with high sequence similarity between human, rat and mouse. Wig-1 belongs to a group of proteins with widely spaced zinc fingers that bind double stranded (ds) RNA. We show here that wig-1 is present in Gallus gallus (chicken), Silurana tropicalis (frog) and Fugu rubripes (fish) by assembly of EST sequence data from a range of data bases into putative cDNAs. The zinc finger regions of Wig-1 are almost completely conserved from fish to man. A short upstream open reading frame is conserved in mammals and birds but not in amphibians. Sequence information from clones of Macaca mulatta (Rhesus macaque), Sus scrofa (pig), Danio rerio (Zebra fish) and Tetraodon nigroviridis (fresh water puffer fish) indicates that Wig-1 orthologs exist also in these species. No genes with striking similarities to wig-1 were found in invertebrates. Our results suggest that Wig-1 and particularly the zinc finger domains have an important biological function in the p53 pathway in vertebrates.