The Drosophila gene abnormal spindle encodes a novel microtubule-associated protein that associates with the polar regions of the mitotic spindle.
abnormal spindle, a gene required for normal spindle structure and function in Drosophila melanogaster, lies immediately adjacent the gene tolloid at 96A/B. It encodes a 220-kD polypeptide with a predicted pI of 10.8. The recessive mutant allele asp1 directs the synthesis of a COOH terminally truncated or internally deleted peptide of approximately 124 kD. Wild-type Asp protein copurifies with microtubules and is not released by salt concentrations known to dissociate most other microtubule-associated proteins. The bacterially expressed NH2-terminal 512-amino acid peptide, which has a number of potential phosphorylation sites for p34(cdc2) and MAP kinases, strongly binds to microtubules. The central 579-amino acid segment of the molecule contains one short motif homologous to sequences in a number of actin bundling proteins and a second motif present at the calmodulin binding sites of several proteins. Immunofluorescence studies show that the wild-type Asp protein is localized to the polar regions of the spindle immediately surrounding the centrosome. These findings are discussed in relation to the known spindle abnormalities in asp mutants.
Saunders
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RD
Cancer Research Campaign, Cell Cycle Genetics Group, Department of Anatomy and Physiology, University of Dundee, Dundee DD1 4HN, Scotland.
Avides
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MC
Howard
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Gonzalez
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Glover
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DM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D008941:Spindle Apparatus / Q000648:ultrastructure*
D002148:Calmodulin-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; C106174:asp protein, Drosophila