Transcriptional Regulation of Catalase Gene in the Fission Yeast Schizosaccharomyces pombe: Molecular Cloning of the Catalase Gene and Northern Blot Analyses of the Transcript

Exposure of Schizosaccharomyces pombe cells to various stresses including 0.2 mM hydrogen peroxide, 50 microM menadione, 10 J/m2 of UV irradiation at 255 nm, and high osmolarity (0.5 M sorbitol or 0.3 M NaCl) induces catalase [EC 1.11.1.6] activity. A part of the catalase gene of S. pombe was amplified by PCR with oligonucleotide primers designed from amino acid sequences conserved in several species of catalases. The catalase gene including its flanking sequence of S. pombe was cloned from a genomic DNA library of S. pombe, which was constructed on the EMBL3 vector, using the PCR-amplified DNA as a radioactive probe. A 3.5 kb HindIII fragment, which hybridized with the PCR-amplified probe, was subcloned into pUC19 and sequenced. The fragment contains one long open reading frame without any intron. The polypeptide deduced from the nucleotide sequence consists of 512 amino acid residues and is homologous to several other catalases. Amino acid sequences of the proteolytic peptides obtained from the purified catalase of S. pombe coincided with the amino acid sequence predicted from the DNA sequence. Transcription of this gene starts at 370 bases upstream of the initiation methionine codon. Northern blot analyses of the catalase mRNA revealed that the stresses which induce the catalase activity also induce the transcription of the catalase gene. The induction of the catalase mRNA by hydrogen peroxide is not inhibited by cycloheximide or staurosporine.