Direct observation of microtubule dynamics inReticulomyxa: Unusually rapid length changes and microtubule sliding

Autor: Yih-Tai Chen, Manfred Schliwa
Rok vydání: 1990
Předmět:
Zdroj: Cell Motility and the Cytoskeleton. 17:214-226
ISSN: 1097-0169
0886-1544
DOI: 10.1002/cm.970170308
Popis: Microtubule dynamics has been studied extensively in vitro, but comparatively little information is available on the in vivo behavior of microtubules. Here we report on the assembly, disassembly, and sliding of microtubules in the giant freshwater amoeba, Reticulomyxa. We have found that treating the cell with 0.25% trypsin induces the rapid formation of exceedingly flat areas within the reticulopodial network, allowing for the direct observation of microtubule behavior by DIC optics and computer-enhanced video microscopy. In flattened areas, microtubule sliding occurs at rates of between 1 and 6.5 μm/sec. The average rate of microtubule assembly is 1.6 μm/sec, while microtubule disassembly takes place at about 4 μm/sec and can reach up to 19.5 μm/sec. We also observed many cases where a microtubule forms a hairpin loop and eventually breaks, resulting in bidirectional disassembly from the point of breakage. Our observations demonstrate sliding of cytoplasmic microtubules in vivo. The high rates of microtubule assembly/disassembly in this cell type are difficult to reconcile with conventional views of association and dissociation processes at microtubule ends and suggest unconventional mechanisms for the growth and shrinkage of microtubules.
Databáze: OpenAIRE
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