Conserved and specific functions of axoneme components in trypanosome motility
Conserved and specific functions of axoneme components in trypanosome motility
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DOI：
10.1242/jcs.03078
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发表时间：
2006-08-15
影响因子：
4
通讯作者：
Bastin, Philippe
中科院分区：
文献类型：
--
作者：
Branche, Carole;Kohl, Linda;Bastin, Philippe
布鲁氏锥虫的鞭毛是不寻常的，因为它依附在细胞体上，除了一个明显常规的轴丝外，还含有一种称为束旁杆的结构，这是细胞运动所必需的。在这里，我们研究了正常和突变锥体细胞系中鞭毛的行为，在这些细胞系中，编码各种轴丝蛋白(PF16、PF20、DNAI1、LC2)的基因的表达已被RNAi沉默。首先，我们证明，在没有动力蛋白外臂的情况下，推进波(通常用于向前运动)被取消，而反向波(通常用于改变方向)仍然发生。第二，与衣藻不同--但与后生动物一样，中央对在鞭毛敲打过程中采用固定的方向。在中央动力蛋白臂突变体和外动力蛋白臂突变体中，这种取向变得非常不同。第三，旁视杆通过促进三维波的传播和控制细胞的形状来促进运动。第四，在寄生虫的昆虫阶段和血液阶段，完成细胞分裂的最后阶段都需要运动性。最后，我们的研究还揭示了锥虫鞭毛的分子组成的保守性。再加上反向遗传学的易用性，它提高了锥虫作为模式生物研究纤毛和鞭毛的兴趣。
The Trypanosoma brucei flagellum is unusual as it is attached along the cell body and contains, in addition to an apparently conventional axoneme, a structure called the paraflagellar rod, which is essential for cell motility. Here, we investigated flagellum behaviour in normal and mutant trypanosome cell lines where expression of genes encoding various axoneme proteins (PF16, PF20, DNAI1, LC2) had been silenced by RNAi. First, we show that the propulsive wave (normally used for forward motility) is abolished in the absence of outer dynein arms, whereas the reverse wave (normally used for changing direction) still occurs. Second, in contrast to Chlamydomonas - but like metazoa, the central pair adopts a fixed orientation during flagellum beating. This orientation becomes highly variable in central-pair- and outer-dynein-arm-mutants. Third, the paraflagellar rod contributes to motility by facilitating three-dimensional wave propagation and controlling cell shape. Fourth, motility is required to complete the last stage of cell division in both insect and bloodstream stages of the parasite. Finally, our study also reveals the conservation of molecular components of the trypanosome flagellum. Coupled to the ease of reverse genetics, it raises the interest of trypanosomes as model organisms to study cilia and flagella.