title: Apoptotic cell death in the fission yeast Schizosaccharomyces pombe induced by valproic acid and its extreme susceptibility to pH change.
abstract: Schizosaccharomyces pombe treated with valproic acid died with apoptotic markers such as DNA fragmentation, loss of a mitochondrial electrochemical gradient and chromatin condensation, independently of metacaspase, a yeast homolog of metazoan caspase. Sensitivity to valproic acid was strongly dependent on growth phase. Cells in a later growth phase were much more sensitive to valproic acid than those in an earlier one. Altering the pH of the medium with HCl and with NaOH also caused remarkable changes in sensitivity. Cells in an acidic medium were more sensitive to valproic acid. This pH-dependent change in sensitivity did not require de novo protein synthesis, and a change in pH 60 min after the administration of valproic acid affected sensitivity. These results suggest that the intracellular cell death process was susceptible to extracellular pH. Although a sir2 mutant of Saccharomyces cerevisiae has been reported to be resistant to valproic acid, mutations in sir2 did not affect the sensitivity to valproic acid of S. pombe.
authors.affiliation: Department of Genetics, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan. normutoh@inst-hsc.jp
authors.forename: Norihiro
authors.initials: N
authors.lastname: Mutoh
authors.forename: Satoko
authors.initials: S
authors.lastname: Kitajima
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Ichihara
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000032:analysis; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D015169:Colony Count, Microbial; D053938:DNA Fragmentation / Q000187:drug effects; D017353:Gene Deletion; D006863:Hydrogen-Ion Concentration; D020287:In Situ Nick-End Labeling; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D029702:Schizosaccharomyces pombe Proteins; C526400:sir2 protein, S pombe; D014635:Valproic Acid; D020169:Caspases