Depletion of syntaxins in the early Caenorhabditis elegans embryo reveals a role for membrane fusion events in cytokinesis.
BACKGROUND
During cytokinesis, the plasma membrane of the parent cell is resolved into the two plasma membranes of the daughter cells. Membrane fusion events mediated by the machinery that participates in intracellular vesicle trafficking might contribute to this process. Two classes of molecules that are required for membrane fusion are the t-SNAREs and the v-SNAREs. The t-SNAREs (syntaxins) comprise a multi-gene family that has been suggested to mediate, at least in part, selective membrane fusion events in the cell.


RESULTS
We have analyzed the genome of Caenorhabditis elegans and identified eight syntaxin genes. RNA-mediated interference (RNAi) was used to produce embryos deficient in individual syntaxins and these embryos were phenotypically characterized. Embryos deficient in one syntaxin, Syn-4, became multinucleate because of defects in karyomere fusion and cytokinesis. Syn-4 localized both to ingressing cleavage furrows and to punctate structures surrounding nuclei as they reformed during interphase.


CONCLUSIONS
Our analyses indicate that both cytokinesis and reformation of the nuclear envelope are dependent on SNARE-mediated membrane fusion.
Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030, Vienna, Austria.
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Jantsch-Plunger
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Glotzer
D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D002455:Cell Division / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D008853:Microscopy; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D016296:Mutagenesis; D009685:Nuclear Envelope / Q000502:physiology; D010641:Phenotype; D010802:Phylogeny; D050765:Qa-SNARE Proteins; D012313:RNA / Q000032:analysis; D011993:Recombinant Fusion Proteins; D013997:Time Factors
D029742:Caenorhabditis elegans Proteins; C490517:MKLP1 protein, C elegans; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D050765:Qa-SNARE Proteins; D011993:Recombinant Fusion Proteins; D012313:RNA