Regulation of cell polarity by microtubules in fission yeast.
To investigate the role of microtubules in regulating cell polarity in Schizosaccharomyces pombe, we have developed a system in which normally cylindrical fission yeast synchronously form branched cells at high frequency upon treatment with the microtubule-depolymerizing drug thiabendazole (TBZ). Branching depends on both elevated temperature and cell cycle state and occurs at high frequency only when TBZ is added to cells that have not yet passed through New-End Take-Off (NETO), the normal transition from monopolar to bipolar growth. This suggests that microtubules may be of greatest physiological importance for the maintenance of cell shape at specific points in the cell cycle. The localization of three different proteins normally found at cell ends-cortical F-actin, tea1, and an ral3 (scd2)-green fluorescent protein (GFP) fusion-is disrupted by TBZ treatment. However, these proteins can eventually return to cell ends in the absence of microtubules, indicating that although their localization to ends normally depends on microtubules, they may recover by alternative mechanisms. In addition, TBZ induces a shift in ral3-GFP distribution from cell ends to the cell middle, suggesting that a protein complex containing ral3 may be part of the cue that specifies the position of branch formation.
Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom. sawin@europa.lif.icnet.uk
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D000199:Actins / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D016764:Cell Polarity / Q000187:drug effects / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins; D013696:Temperature; D013827:Thiabendazole / Q000494:pharmacology
D000199:Actins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C089770:scd2 protein, S pombe; D049452:Green Fluorescent Proteins; D013827:Thiabendazole