title: Fission yeast Sap1 protein is essential for chromosome stability.
abstract: Sap1 is a dimeric sequence-specific DNA binding-protein, initially identified for its role in mating-type switching of the fission yeast Schizosaccharomyces pombe. The protein is relatively abundant, around 10,000 dimers/cell, and is localized in the nucleus. sap1+ is essential for viability, and transient overexpression is accompanied by rapid cell death, without an apparent checkpoint response and independently of mating-type switching. Time lapse video microscopy of living cells revealed that the loss of viability is accompanied by abnormal mitosis and chromosome fragmentation. Overexpression of the C terminus of Sap1 induces minichromosome loss associated with the "cut" phenotype (uncoupling mitosis and cytokinesis). These phenotypes are favored when the C terminus of Sap1 is overexpressed during DNA replication. Fluorescence in situ hybridization experiments demonstrated that the cut phenotype is related to precocious centromere separation, a typical marker for loss of cohesion. We propose that Sap1 is an architectural chromatin-associated protein, required for chromosome organization.
authors.affiliation: Dynamique du Genome, URA 1644 du CNRS, Institut Pasteur, 75724 Paris 15, France.
authors.forename: Raynald
authors.initials: R
authors.lastname: de Lahondès
authors.forename: Veronique
authors.initials: V
authors.lastname: Ribes
authors.forename: Benoit
authors.initials: B
authors.lastname: Arcangioli
mesh_terms: D000705:Anaphase / Q000502:physiology; D001562:Benzimidazoles / Q000494:pharmacology; D015139:Blotting, Southern; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002503:Centromere / Q000502:physiology; D002843:Chromatin / Q000378:metabolism; D043171:Chromosomal Instability / Q000235:genetics / Q000502:physiology*; D019457:Chromosome Breakage / Q000502:physiology; D020090:Chromosome Segregation / Q000502:physiology; D015825:Chromosomes, Fungal / Q000502:physiology; D004271:DNA, Fungal / Q000032:analysis; D004278:DNA, Superhelical / Q000502:physiology; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015966:Gene Expression Regulation, Fungal; D020043:Genes, Essential / Q000235:genetics; D006918:Hydroxyurea / Q000494:pharmacology; D017404:In Situ Hybridization, Fluorescence; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000502:physiology; D009690:Nucleic Acid Conformation; D010641:Phenotype; D016196:S Phase / Q000502:physiology; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology; D013827:Thiabendazole / Q000494:pharmacology; D014162:Transfection
chemical_list: D001562:Benzimidazoles; D002843:Chromatin; D004271:DNA, Fungal; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; C085981:Sap1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D013827:Thiabendazole; C017807:bisbenzimide ethoxide trihydrochloride; D006918:Hydroxyurea