title: Mast, a conserved microtubule-associated protein required for bipolar mitotic spindle organization.
abstract: Through mutational analysis in Drosopjila we have identified the gene multiple asters (mast), which encodes a new 165 kDa protein. mast mutant neuroblasts are highly polyploid and show severe mitotic abnormalities including the formation of mono- and multi-polar spindles organized by an irregular number of microtubule-organizing centres of abnormal size and shape. The mast gene product is evolutionarily conserved since homologues were identified from yeast to man, revealing a novel protein family. Antibodies against Mast and analysis of tissue culture cells expressing an enhanced green fluorescent protein-Mast fusion protein show that during mitosis, this protein localizes to centrosomes, the mitotic spindle, centromeres and spindle midzone. Microtubule-binding assays indicate that Mast is a microtubule-associated protein displaying strong affinity for polymerized microtubules. The defects observed in the mutant alleles and the intracellular localization of the protein suggest that Mast plays an essential role in centrosome separation and organization of the bipolar mitotic spindle.
authors.affiliation: Laboratório de Genética Molecular da Mitose, Instituto de Biologia Molecular e Celular, Universidade do Porto, R.Campo Alegre, 823, 4150-180 Porto, Portugal.
authors.forename: C L
authors.initials: CL
authors.lastname: Lemos
authors.forename: P
authors.initials: P
authors.lastname: Sampaio
authors.forename: H
authors.initials: H
authors.lastname: Maiato
authors.forename: M
authors.initials: M
authors.lastname: Costa
authors.forename: L V
authors.initials: LV
authors.lastname: Omel'yanchuk
authors.forename: V
authors.initials: V
authors.lastname: Liberal
authors.forename: C E
authors.initials: CE
authors.lastname: Sunkel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D002478:Cells, Cultured; D018385:Centrosome / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D003001:Cloning, Molecular; D003078:Colchicine / Q000494:pharmacology; D017124:Conserved Sequence; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000187:drug effects / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010802:Phylogeny; D011485:Protein Binding; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D008941:Spindle Apparatus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C407307:chb protein, Drosophila; D049452:Green Fluorescent Proteins; D003078:Colchicine