title: SPD-3 is required for spindle alignment in Caenorhabditis elegans embryos and localizes to mitochondria.
abstract: During the development of multicellular organisms, cellular diversity is often achieved through asymmetric cell divisions that produce two daughter cells having different developmental potentials. Prior to an asymmetric cell division, cellular components segregate to opposite ends of the cell defining an axis of polarity. The mitotic spindle rotationally aligns along this axis of polarity, thereby ensuring that the cleavage plane is positioned such that segregated components end up in individual daughter cells. Here we report our characterization of a novel gene required for spindle alignment in Caenorhabditis elegans. During the first mitosis in spd-3(oj35) embryos the spindle failed to align along the anterior/posterior axis, leading to abnormal cleavage configurations. spd-3(oj35) embryos had additional defects reminiscent of dynein/dynactin loss-of-function possibly caused by the mislocalization of dynactin. Surprisingly, we found that SPD-3GFP localized to mitochondria. Consistent with this localization, spd-3(oj35) worms exhibited slow growth and increased ATP concentrations, which are phenotypes similar to those described for other mitochondrial mutants in C. elegans. To our knowledge, SPD-3 is the first example of a link between mitochondria and spindle alignment in C. elegans.
authors.affiliation: Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Dinkelmann
authors.forename: Haining
authors.initials: H
authors.lastname: Zhang
authors.forename: Ahna R
authors.initials: AR
authors.lastname: Skop
authors.forename: John G
authors.initials: JG
authors.lastname: White
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018509:DNA, Helminth / Q000235:genetics; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism; D005260:Female; D017238:Genes, Helminth; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008540:Meiosis / Q000235:genetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D034622:RNA Interference; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D018509:DNA, Helminth; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; C582282:SPD-3 protein, C elegans; D049452:Green Fluorescent Proteins; D004398:Dyneins