Gamma-tubulin and the C-terminal motor domain kinesin-like protein, KLPA, function in the establishment of spindle bipolarity in Aspergillus nidulans.
Gamma-tubulin and the C-terminal motor domain kinesin-like protein, KLPA, function in the establishment of spindle bipolarity in Aspergillus nidulans.
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DOI：
10.1091/mbc.12.10.3161
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发表时间：
2001-10
影响因子：
3.3
通讯作者：
N. Prigozhina;Richard A. Walker;C. Oakley;B. Oakley
中科院分区：
文献类型：
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作者：
N. Prigozhina;Richard A. Walker;C. Oakley;B. Oakley
先前的研究已经发现，裂殖酵母中的γ-微管蛋白突变是合成致死的，其C-末端运动结构域驱动蛋白样蛋白基因pkl 1缺失，但是双突变体的致死性阻止了合成相互作用的表型分析。我们研究了klpA 1（pkl 1的构巢曲霉同源物的缺失）和mipA（γ-微管蛋白基因）突变之间的相互作用。我们发现，klpA 1显着增加冷敏感性，并略有降低在所有温度下的生长速率，三个mipA等位基因。在同步化的细胞中，我们发现klpA 1导致纺锤体双极性建立的实质性但短暂的抑制。在限制性温度下，mipAD 123引起纺锤体双极性的轻微、短暂的抑制和后期A的更显著的抑制。在mipAD 123/klpA 1菌株中，双极纺锤体的形成比在klpA 1单突变体中受到更强烈的抑制，并且许多纺锤体显然永远不会变成双极的。令人惊讶的是，这些结果表明，γ-微管蛋白和klpA驱动蛋白在纺锤体双极性的建立中具有重叠的作用。我们提出了一个模型来解释这些数据。
Previous research has found that a gamma-tubulin mutation in Schizosaccharomyces pombe is synthetically lethal with a deletion of the C-terminal motor domain kinesin-like protein gene pkl1, but the lethality of the double mutant prevents a phenotypic analysis of the synthetic interaction. We have investigated interactions between klpA1, a deletion of an Aspergillus nidulans homolog of pkl1, and mutations in the mipA, gamma-tubulin gene. We find that klpA1 dramatically increases the cold sensitivity and slightly reduces the growth rate at all temperatures, of three mipA alleles. In synchronized cells we find that klpA1 causes a substantial but transient inhibition of the establishment of spindle bipolarity. At a restrictive temperature, mipAD123 causes a slight, transient inhibition of spindle bipolarity and a more significant inhibition of anaphase A. In the mipAD123/klpA1 strain, formation of bipolar spindles is more strongly inhibited than in the klpA1 single mutant and many spindles apparently never become bipolar. These results indicate, surprisingly, that gamma-tubulin and the klpA kinesin have overlapping roles in the establishment of spindle bipolarity. We propose a model to account for these data.