Science：揭示中心体基体车轮状结构

7月12日，<em>Science</em>在线报道了中心体基体车轮状结构的最新研究进展，为深入理解诸多有丝分裂异常相关疾病：如肿瘤和某些染色体核型异常遗传病，打下了良好的基础。

中心粒和基体对于纤毛，鞭毛，中心体的形成至关重要。中心粒和基体表现为特征性的九倍对称车轮状结构，包含一系列SAS-6蛋白环。

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研究者使用冷冻电子断层成像技术研究鞭毛披发虫（flagellate Trichonympha）特别长的车轮结构。结果发现，车轮是一摞垂直周期性为8.5纳米，能容纳9个SAS-6蛋白同源二聚体的中央环。从两个这样的环散发出的辐条状结构，连结为一个垂直周期性为17纳米的层状结构，环绕于车轮状结构边缘。

由此，利用生物多样性的便利，研究者揭示了中心粒和基体的九倍对称性车轮结构。 
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<img src="http://www.bioon.com/biology/UploadFiles/201207/2012071311374988.gif" alt="" width="113" height="149" border="0" hspace="0" />

<a title="" href="http://dx.doi.org/10.1016/j.cell.2011.10.017" target="_blank">doi:</a><a title="" href="http://www.sciencemag.org/content/early/2012/07/11/science.1222789" target="_blank">10.1016/j.cell.2011.10.017</a>
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<br/><strong>Cartwheel Architecture of Trichonympha Basal Body </strong><br/>


Paul Guichard1,Ambroise Desfosses2,Aditi Maheshwari3,Virginie Hachet1,Carsten Dietrich4,Andreas Brune4,Takashi Ishikawa3,Carsten Sachse2,Pierre G?nczy1

Centrioles and basal bodies are essential for the formation of cilia, flagella, and centrosomes. Centrioles and basal bodies exhibit a characteristic ninefold symmetry imparted by a cartwheel thought to contain rings of SAS-6 proteins. We used cryoelectron tomography to investigate the architecture of the exceptionally long cartwheel of the flagellate Trichonympha. We found that the cartwheel is a stack of central rings that exhibit a vertical periodicity of 8.5 nanometers and able to accommodate nine SAS-6 homodimers. The spokes that emanate from two such rings associate into a layer, with a vertical periodicity of 17 nanometers on the cartwheel margin. Thus, by using the power of biodiversity, we unveiled the architecture of the cartwheel at the root of the ninefold symmetry of centrioles and basal bodies.

<br/>来源：生物谷

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