title: Condensin HEAT subunits required for DNA repair, kinetochore/centromere function and ploidy maintenance in fission yeast.
abstract: Condensin, a central player in eukaryotic chromosomal dynamics, contains five evolutionarily-conserved subunits. Two SMC (structural maintenance of chromosomes) subunits contain ATPase, hinge, and coiled-coil domains. One non-SMC subunit is similar to bacterial kleisin, and two other non-SMC subunits contain HEAT (similar to armadillo) repeats. Here we report isolation and characterization of 21 fission yeast (Schizosaccharomyces pombe) mutants for three non-SMC subunits, created using error-prone mutagenesis that resulted in single-amino acid substitutions. Beside condensation, segregation, and DNA repair defects, similar to those observed in previously isolated SMC and cnd2 mutants, novel phenotypes were observed for mutants of HEAT-repeats containing Cnd1 and Cnd3 subunits. cnd3-L269P is hypersensitive to the microtubule poison, thiabendazole, revealing defects in kinetochore/centromere and spindle assembly checkpoints. Three cnd1 and three cnd3 mutants increased cell size and doubled DNA content, thereby eliminating the haploid state. Five of these mutations reside in helix B of HEAT repeats. Two non-SMC condensin subunits, Cnd1 and Cnd3, are thus implicated in ploidy maintenance.
authors.affiliation: Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan; Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
authors.forename: Xingya
authors.initials: X
authors.lastname: Xu
authors.affiliation: Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Nakazawa
authors.affiliation: Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yanagida
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002503:Centromere / Q000187:drug effects / Q000378:metabolism*; D015825:Chromosomes, Fungal; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011003:Ploidies; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D013827:Thiabendazole / Q000494:pharmacology
chemical_list: D018797:Cell Cycle Proteins; C000604342:Cnd1 protein, S pombe; C454839:Cnd2 protein, S pombe; C000604343:Cnd3 protein, S pombe; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D029702:Schizosaccharomyces pombe Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases; D013827:Thiabendazole