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.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
-
Anaphase / physiology
-
Benzimidazoles / pharmacology
-
Blotting, Southern
-
Blotting, Western
-
Cell Division / drug effects
-
Cell Division / genetics
-
Cell Division / physiology
-
Centromere / physiology
-
Chromatin / metabolism
-
Chromosomal Instability / genetics
-
Chromosomal Instability / physiology*
-
Chromosome Breakage / physiology
-
Chromosome Segregation / physiology
-
Chromosomes, Fungal / physiology
-
DNA, Fungal / analysis
-
DNA, Superhelical / physiology
-
DNA-Binding Proteins / deficiency
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / physiology*
-
Electrophoresis, Gel, Pulsed-Field
-
Flow Cytometry
-
Fluorescent Antibody Technique
-
Gene Expression Regulation, Fungal
-
Genes, Essential / genetics
-
Hydroxyurea / pharmacology
-
In Situ Hybridization, Fluorescence
-
Microscopy, Fluorescence
-
Mitosis / physiology
-
Nucleic Acid Conformation
-
Phenotype
-
S Phase / physiology
-
Schizosaccharomyces / genetics
-
Schizosaccharomyces / growth & development
-
Schizosaccharomyces / physiology*
-
Schizosaccharomyces pombe Proteins / genetics
-
Schizosaccharomyces pombe Proteins / physiology*
-
Spindle Apparatus / physiology
-
Thiabendazole / pharmacology
-
Transfection
Substances
-
Benzimidazoles
-
Chromatin
-
DNA, Fungal
-
DNA, Superhelical
-
DNA-Binding Proteins
-
Sap1 protein, S pombe
-
Schizosaccharomyces pombe Proteins
-
Thiabendazole
-
bisbenzimide ethoxide trihydrochloride
-
Hydroxyurea