Superinduction of the catalase gene was observed in Schizosaccharomyces pombe cells treated with cycloheximide and hydrogen peroxide. The promoter analysis of the catalase gene revealed that element A (the region from -111 to -90, numbered with the transcription start site as +1), involved in the induction of the gene under oxidative stress, was required for superinduction by hydrogen peroxide and cycloheximide. Although Atf1 is a transcription factor responsible for the induction of the catalase gene by several stresses, a disruptant of atf1 exhibited superinduction. Moreover, in a deletion mutant that lacks element A but has an Atf1 binding site, the cells treated with hydrogen peroxide and cycloheximide expressed as much catalase mRNA as those treated with hydrogen peroxide alone. This suggests that cycloheximide does not stabilize the catalase mRNA but enhances the transcription via element A. Staurosporine, a strong inhibitor of protein phosphorylation, did not inhibit superinduction.