Searching the EST database with the newly discovered C.elegans antizyme identi®ed antizyme orthologs in four other nematode species. In two cases (Necator americanus and Haemonchus contortus), the cDNA sequences in the database were suf®cient to make contigs of the complete coding regions. In the other two cases [Onchocerca volvulus (DDBJ/EMBL/GenBank accession No. AF217279) and Pristioncus paci®cus (DDBJ/EMBL/ GenBank accession No. AF217280)] the complete cDNA sequences were obtained by PCR amplifying and sequencing the full genes from cDNA libraries. As with the previously identi®ed eukaryotic antizyme genes, the ORF con®guration of the newly found nematode orthologs implies the necessity for +1 frameshifting for synthesis of full-length protein.