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The shape of plant cells depends on cortical microtubules. Their freedom from central microtubule organizing centres provides a powerful experimental system to study microtubule self-organization. New ideas have emerged from live-cell imaging of microtubules, particularly in the model system Arabidopsis thaliana, revealing the importance of encounters(More)
Diverse kinesin motor proteins are involved in spindle function; however, the mechanisms by which they are targeted to specific sites within spindles are not well understood. Here, we show that a fusion between yellow fluorescent protein (YFP) and a minus-end-directed Kinesin-14 (C-terminal family) from Arabidopsis, ATK5, localizes to mitotic spindle(More)
During cell division, the mitotic spindle partitions chromosomes into daughter nuclei. In higher plants, the molecular mechanisms governing spindle assembly and function remain largely unexplored. Here, live cell imaging of mitosis in Arabidopsis thaliana plants lacking a kinesin-14 (ATK5) reveals defects during early spindle formation. Beginning during(More)
Controlling microtubule dynamics and spatial organization is a fundamental requirement of eukaryotic cell function. Members of the ORBIT/MAST/CLASP family of microtubule-associated proteins associate with the plus ends of microtubules, where they promote the addition of tubulin subunits into attached kinetochore fibers during mitosis and stabilize(More)
CLASP proteins associate with either the plus ends or sidewalls of microtubules depending on the subcellular location and cell type. In plant cells, CLASP's distribution along the full length of microtubules corresponds with the uniform anchorage of microtubules to the cell cortex. Using live cell imaging, we show here that loss of CLASP in Arabidopsis(More)
In higher plants, the preprophase band (PPB) of microtubules (MTs) forecasts the cell division site prior to mitosis and specifies the organization of MTs into a bipolar prophase spindle surrounding the nucleus. However, the mechanisms governing this PPB-dependent establishment of bipolarity are unclear. Here, we present evidence from live cell imaging(More)
The microtubule cytoskeleton forms the scaffolding of the meiotic spindle. Kinesins, which bind to microtubules and generate force via ATP hydrolysis, are also thought to play a critical role in spindle assembly, maintenance, and function. The A. thaliana protein, ATK1 (formerly known as KATA), is a member of the kinesin family based on sequence similarity(More)
Microtubules anchored to the two-dimensional cortex of plant cells collide through plus-end polymerization. Collisions can result in rapid depolymerization, directional plus-end entrainment, or crossover. These interactions are believed to give rise to cellwide self-organization of plant cortical microtubules arrays, which is required for proper cell wall(More)
Gene duplication is important for gene family evolution, allowing for functional divergence and innovation. In flowering plants, duplicated genes are widely observed, and functional redundancy of closely related duplicates has been reported, but few cases of functional divergence of close duplicates have been described. Here, we show that the Arabidopsis(More)
We have developed a 4D computer-assisted reconstruction and motion analysis system, J3D-DIAS 4.1, and applied it to the reconstruction and motion analysis of tumorigenic cells in a 3D matrix. The system is unique in that it is fast, high-resolution, acquires optical sections using DIC microscopy (hence there is no associated photoxicity), and is capable of(More)