p93dis1, which is required for sister chromatid separation, is a novel microtubule and spindle pole body-associating protein phosphorylated at the Cdc2 target sites.
Fission yeast cold-sensitive (cs) dis1 mutants are defective in sister chromatid separation. The dis1+ gene was isolated by chromosome walking. The null mutant showed the same phenotype as that of cs mutants. The dis1+ gene product was identified as a novel 93-kD protein, and its localization was determined by use of anti-dis1 antibodies and green fluorescent protein (GFP) tagged to the carboxyl end of p93dis1. The tagged p93dis1 in living cells localizes along cytoplasmic microtubule arrays in interphase and the elongating anaphase spindle in mitosis, but association with the short metaphase spindle microtubules is strikingly reduced. In the spindle, the tagged p93dis1 is enriched at the spindle pole bodies (SPBs). Time-lapse video images of single cells support the localization shift of p93dis1 to the SPBs in metaphase and spindle microtubules in anaphase. The carboxy-terminal fragment, which is essential for Dis1 function, accumulates around the mitotic SPB. We propose that these localization shifts of p93dis1 in mitosis facilitates sister chromatid separation by affecting SPB and anaphase spindle function.
Nabeshima
K
K
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Kurooka
H
H
Takeuchi
M
M
Kinoshita
K
K
Nakaseko
Y
Y
Yanagida
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002842:Chromatids / Q000378:metabolism* / Q000648:ultrastructure; D003360:Cosmids; D005656:Fungal Proteins / Q000378:metabolism*; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins; D006801:Humans; D007399:Interphase; D008164:Luminescent Proteins / Q000032:analysis / Q000096:biosynthesis; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016296:Mutagenesis; D010766:Phosphorylation; D010957:Plasmids; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000378:metabolism*
D005656:Fungal Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins; C094879:dis1 protein, S pombe; D049452:Green Fluorescent Proteins; D016203:CDC2 Protein Kinase